diff --git a/packages/accounts-controller/CHANGELOG.md b/packages/accounts-controller/CHANGELOG.md
index fbf98f64b2d..e68e2aebfb5 100644
--- a/packages/accounts-controller/CHANGELOG.md
+++ b/packages/accounts-controller/CHANGELOG.md
@@ -7,9 +7,25 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add `init` method and `AccountsController:init` messenger action ([#10191](https://github.com/MetaMask/core/pull/10191))
+  - Loads accounts from the current keyring state, intended to pair with `clearState` for wallet reset flows (`clearState` then `init`).
+  - Idempotent: subsequent calls before `clearState` are no-ops.
+  - Fires `AccountsController:accountsAdded` for accounts newly discovered during initialization.
+  - Fires `AccountsController:initialized` (with current state as payload) when initialization completes.
+- Add `AccountsController:initialized` event - fired by `init()` when the controller finishes its first full account sync ([#10191](https://github.com/MetaMask/core/pull/10191))
+- Add `AccountsController:uninitialized` event - fired by `clearState()` to signal that `init()` must be called again ([#10191](https://github.com/MetaMask/core/pull/10191))
+
 ### Changed
 
 - Bump `uuid` from `^8.3.2` to `^9.0.1` ([#10117](https://github.com/MetaMask/core/pull/10117))
+- `clearState()` now resets the initialized flag and fires `AccountsController:uninitialized` ([#10191](https://github.com/MetaMask/core/pull/10191))
+
+### Removed
+
+- **BREAKING:** Remove `updateAccounts` method and `AccountsController:updateAccounts` messenger action ([#10191](https://github.com/MetaMask/core/pull/10191))
+  - Use `AccountsController:init` instead, it performs the same full keyring sync and additionally fires lifecycle events.
 
 ## [40.0.0]
 
diff --git a/packages/accounts-controller/src/AccountsController-method-action-types.ts b/packages/accounts-controller/src/AccountsController-method-action-types.ts
index ba571bac364..5605fbb1f66 100644
--- a/packages/accounts-controller/src/AccountsController-method-action-types.ts
+++ b/packages/accounts-controller/src/AccountsController-method-action-types.ts
@@ -151,16 +151,19 @@ export type AccountsControllerUpdateAccountMetadataAction = {
 };
 
 /**
- * Updates the internal accounts list by retrieving normal and snap accounts,
- * removing duplicates, and updating the metadata of each account.
+ * Initializes the controller by loading accounts from the current keyring
+ * state. Any accounts present in the keyrings but missing from the
+ * controller's state are added; existing accounts are preserved.
+ *
+ * Intended to be called after {@link clearState} to restore accounts from
+ * the keyrings (i.e. `clearState` then `init`), or on first startup.
  *
  * @deprecated This method is deprecated and will be removed in a future version.
  * Use `AccountTreeController`, `MultichainAccountService`, or the Keyring API v2 instead.
- * @returns A Promise that resolves when the accounts have been updated.
  */
-export type AccountsControllerUpdateAccountsAction = {
-  type: `AccountsController:updateAccounts`;
-  handler: AccountsController['updateAccounts'];
+export type AccountsControllerInitAction = {
+  type: `AccountsController:init`;
+  handler: AccountsController['init'];
 };
 
 /**
@@ -201,6 +204,6 @@ export type AccountsControllerMethodActions =
   | AccountsControllerSetAccountNameAction
   | AccountsControllerSetAccountNameAndSelectAccountAction
   | AccountsControllerUpdateAccountMetadataAction
-  | AccountsControllerUpdateAccountsAction
+  | AccountsControllerInitAction
   | AccountsControllerLoadBackupAction
   | AccountsControllerClearStateAction;
diff --git a/packages/accounts-controller/src/AccountsController.test.ts b/packages/accounts-controller/src/AccountsController.test.ts
index b8deb353ba2..0f96e16b320 100644
--- a/packages/accounts-controller/src/AccountsController.test.ts
+++ b/packages/accounts-controller/src/AccountsController.test.ts
@@ -2331,7 +2331,7 @@ describe('AccountsController', () => {
     });
   });
 
-  describe('updateAccounts', () => {
+  describe('#sync', () => {
     const mockAddress1 = '0x123';
     const mockAddress2 = '0x456';
     let mockSnapAccount: InternalAccount;
@@ -2434,7 +2434,7 @@ describe('AccountsController', () => {
       ];
       mockUUIDWithNormalAccounts(expectedAccounts);
 
-      await accountsController.updateAccounts();
+      accountsController.init();
 
       expect(accountsController.listMultichainAccounts()).toStrictEqual(
         expectedAccounts,
@@ -2505,7 +2505,7 @@ describe('AccountsController', () => {
 
       const expectedAccounts = [expectedAccount1, expectedAccount2];
 
-      await accountsController.updateAccounts();
+      accountsController.init();
 
       expect(
         accountsController
@@ -2539,7 +2539,7 @@ describe('AccountsController', () => {
 
       const expectedAccounts: InternalAccount[] = [];
 
-      await accountsController.updateAccounts();
+      accountsController.init();
 
       expect(accountsController.listMultichainAccounts()).toStrictEqual(
         expectedAccounts,
@@ -2605,7 +2605,7 @@ describe('AccountsController', () => {
       ];
       mockUUIDWithNormalAccounts(expectedAccounts);
 
-      await accountsController.updateAccounts();
+      accountsController.init();
 
       expect(accountsController.listMultichainAccounts()).toStrictEqual(
         expectedAccounts,
@@ -2678,7 +2678,7 @@ describe('AccountsController', () => {
         }),
       ];
 
-      await accountsController.updateAccounts();
+      accountsController.init();
 
       expect(accountsController.listMultichainAccounts()).toStrictEqual(
         expectedAccounts,
@@ -2744,7 +2744,7 @@ describe('AccountsController', () => {
         }),
       ];
 
-      await accountsController.updateAccounts();
+      accountsController.init();
 
       expect(accountsController.listMultichainAccounts()).toStrictEqual(
         expectedAccounts,
@@ -2810,7 +2810,7 @@ describe('AccountsController', () => {
         }),
       ];
 
-      await accountsController.updateAccounts();
+      accountsController.init();
 
       expect(accountsController.listMultichainAccounts()).toStrictEqual(
         expectedAccounts,
@@ -2883,7 +2883,7 @@ describe('AccountsController', () => {
         }),
       ];
 
-      await accountsController.updateAccounts();
+      accountsController.init();
 
       expect(accountsController.listMultichainAccounts()).toStrictEqual(
         expectedAccounts,
@@ -2950,7 +2950,7 @@ describe('AccountsController', () => {
         }),
       ];
 
-      await accountsController.updateAccounts();
+      accountsController.init();
 
       expect(
         accountsController
@@ -2991,7 +2991,7 @@ describe('AccountsController', () => {
         messenger,
       });
 
-      await expect(accountsController.updateAccounts()).rejects.toThrow(
+      expect(() => accountsController.init()).toThrow(
         'Unknown keyring unknown',
       );
     });
@@ -3094,7 +3094,7 @@ describe('AccountsController', () => {
           messenger,
         });
 
-        await accountsController.updateAccounts();
+        accountsController.init();
 
         const selectedAccount = accountsController.getSelectedAccount();
 
@@ -3180,7 +3180,7 @@ describe('AccountsController', () => {
       });
 
       // Will automatically re-create the internal account list.
-      await accountsController.updateAccounts();
+      accountsController.init();
 
       const account = accountsController.getAccount(mockHdSnapAccount.id);
       expect(account?.options).toStrictEqual({
@@ -3270,7 +3270,7 @@ describe('AccountsController', () => {
       });
 
       // Will automatically re-create the internal account list.
-      await accountsController.updateAccounts();
+      accountsController.init();
 
       // This account has been skipped.
       expect(
@@ -3334,7 +3334,7 @@ describe('AccountsController', () => {
         messenger,
       });
 
-      await accountsController.updateAccounts();
+      accountsController.init();
 
       const accounts = accountsController.listMultichainAccounts();
       expect(accounts).toHaveLength(1);
@@ -3386,7 +3386,7 @@ describe('AccountsController', () => {
         messenger,
       });
 
-      await accountsController.updateAccounts();
+      accountsController.init();
 
       expect(accountsController.listMultichainAccounts()).toStrictEqual([]);
     });
@@ -3396,6 +3396,206 @@ describe('AccountsController', () => {
     );
   });
 
+  describe('init', () => {
+    function setupInitTest(): ReturnType<typeof setupAccountsController> {
+      const messenger = buildMessenger();
+      messenger.registerActionHandler(
+        'KeyringController:getState',
+        mockGetState.mockReturnValue({ keyrings: [] }),
+      );
+      messenger.registerActionHandler(
+        'KeyringController:getKeyringsByType',
+        mockGetKeyringByType.mockReturnValue([]),
+      );
+      return setupAccountsController({ messenger });
+    }
+
+    it('runs the internal sync', async () => {
+      const { accountsController } = setupInitTest();
+
+      // Verify init completes without throwing — the sync ran if no error occurs
+      expect(() => accountsController.init()).not.toThrow();
+    });
+
+    it('is a no-op on subsequent calls', async () => {
+      const { accountsController, messenger } = setupInitTest();
+
+      const initializedListener = jest.fn();
+      messenger.subscribe(
+        'AccountsController:initialized',
+        initializedListener,
+      );
+
+      accountsController.init();
+      accountsController.init();
+
+      // initialized event fires exactly once
+      expect(initializedListener).toHaveBeenCalledTimes(1);
+    });
+
+    it('fires accountsAdded for accounts not previously in state', async () => {
+      const messenger = buildMessenger();
+      messenger.registerActionHandler(
+        'KeyringController:getState',
+        mockGetState.mockReturnValue({
+          keyrings: [
+            {
+              type: KeyringTypes.hd,
+              accounts: [mockAccount.address],
+              metadata: { id: 'mock-id', name: 'mock-name' },
+            },
+          ],
+        }),
+      );
+      messenger.registerActionHandler(
+        'KeyringController:getKeyringsByType',
+        mockGetKeyringByType.mockReturnValue([]),
+      );
+      mockUUIDWithNormalAccounts([mockAccount]);
+
+      const { accountsController } = setupAccountsController({
+        initialState: getDefaultAccountsControllerState(),
+        messenger,
+      });
+
+      const accountsAddedListener = jest.fn();
+      messenger.subscribe(
+        'AccountsController:accountsAdded',
+        accountsAddedListener,
+      );
+
+      accountsController.init();
+
+      expect(accountsAddedListener).toHaveBeenCalledTimes(1);
+      expect(accountsAddedListener.mock.calls[0][0]).toHaveLength(1);
+    });
+
+    it('does not fire accountsAdded for accounts already in state', async () => {
+      const messenger = buildMessenger();
+      messenger.registerActionHandler(
+        'KeyringController:getState',
+        mockGetState.mockReturnValue({
+          keyrings: [
+            {
+              type: KeyringTypes.hd,
+              accounts: [mockAccount.address],
+              metadata: { id: 'mock-id', name: 'mock-name' },
+            },
+          ],
+        }),
+      );
+      messenger.registerActionHandler(
+        'KeyringController:getKeyringsByType',
+        mockGetKeyringByType.mockReturnValue([]),
+      );
+      mockUUIDWithNormalAccounts([mockAccount]);
+
+      const { accountsController } = setupAccountsController({
+        initialState: {
+          internalAccounts: {
+            accounts: { [mockAccount.id]: mockAccount },
+            selectedAccount: mockAccount.id,
+          },
+          accountIdByAddress: { [mockAccount.address]: mockAccount.id },
+        },
+        messenger,
+      });
+
+      const accountsAddedListener = jest.fn();
+      messenger.subscribe(
+        'AccountsController:accountsAdded',
+        accountsAddedListener,
+      );
+
+      accountsController.init();
+
+      expect(accountsAddedListener).not.toHaveBeenCalled();
+    });
+
+    it('fires accountsRemoved for accounts dropped by the keyring rebuild', async () => {
+      const messenger = buildMessenger();
+      messenger.registerActionHandler(
+        'KeyringController:getState',
+        // keyrings are now empty — mockAccount is no longer in any keyring
+        mockGetState.mockReturnValue({ keyrings: [] }),
+      );
+      messenger.registerActionHandler(
+        'KeyringController:getKeyringsByType',
+        mockGetKeyringByType.mockReturnValue([]),
+      );
+
+      const { accountsController } = setupAccountsController({
+        initialState: {
+          internalAccounts: {
+            accounts: { [mockAccount.id]: mockAccount },
+            selectedAccount: mockAccount.id,
+          },
+          accountIdByAddress: { [mockAccount.address]: mockAccount.id },
+        },
+        messenger,
+      });
+
+      const accountsRemovedListener = jest.fn();
+      messenger.subscribe(
+        'AccountsController:accountsRemoved',
+        accountsRemovedListener,
+      );
+
+      accountsController.init();
+
+      expect(accountsRemovedListener).toHaveBeenCalledTimes(1);
+      expect(accountsRemovedListener).toHaveBeenCalledWith([mockAccount.id]);
+    });
+
+    it('fires the initialized event with current state', async () => {
+      const { accountsController, messenger } = setupInitTest();
+
+      const initializedListener = jest.fn();
+      messenger.subscribe(
+        'AccountsController:initialized',
+        initializedListener,
+      );
+
+      accountsController.init();
+
+      expect(initializedListener).toHaveBeenCalledTimes(1);
+      expect(initializedListener).toHaveBeenCalledWith(
+        accountsController.state,
+      );
+    });
+
+    it('does not fire initialized on subsequent calls', async () => {
+      const { accountsController, messenger } = setupInitTest();
+
+      const initializedListener = jest.fn();
+      messenger.subscribe(
+        'AccountsController:initialized',
+        initializedListener,
+      );
+
+      accountsController.init();
+      accountsController.init();
+
+      expect(initializedListener).toHaveBeenCalledTimes(1);
+    });
+
+    it('runs again after clearState resets the flag', async () => {
+      const { accountsController, messenger } = setupInitTest();
+
+      const initializedListener = jest.fn();
+      messenger.subscribe(
+        'AccountsController:initialized',
+        initializedListener,
+      );
+
+      accountsController.init();
+      accountsController.clearState();
+      accountsController.init();
+
+      expect(initializedListener).toHaveBeenCalledTimes(2);
+    });
+  });
+
   describe('clearState', () => {
     it('resets state to the default values', () => {
       const { accountsController } = setupAccountsController({
@@ -3452,6 +3652,20 @@ describe('AccountsController', () => {
         getDefaultAccountsControllerState(),
       );
     });
+
+    it('fires the uninitialized event', () => {
+      const { accountsController, messenger } = setupAccountsController({});
+
+      const uninitializedListener = jest.fn();
+      messenger.subscribe(
+        'AccountsController:uninitialized',
+        uninitializedListener,
+      );
+
+      accountsController.clearState();
+
+      expect(uninitializedListener).toHaveBeenCalledTimes(1);
+    });
   });
 
   describe('loadBackup', () => {
@@ -4511,7 +4725,6 @@ describe('AccountsController', () => {
       jest.spyOn(AccountsController.prototype, 'listAccounts');
       jest.spyOn(AccountsController.prototype, 'listMultichainAccounts');
       jest.spyOn(AccountsController.prototype, 'setAccountName');
-      jest.spyOn(AccountsController.prototype, 'updateAccounts');
       jest.spyOn(AccountsController.prototype, 'getAccountByAddress');
       jest.spyOn(AccountsController.prototype, 'getSelectedAccount');
       jest.spyOn(AccountsController.prototype, 'getAccount');
@@ -4677,8 +4890,8 @@ describe('AccountsController', () => {
       });
     });
 
-    describe('updateAccounts', () => {
-      it('update accounts', async () => {
+    describe('init', () => {
+      it('is callable via the messenger and fires initialized event', async () => {
         const messenger = buildMessenger();
         messenger.registerActionHandler(
           'KeyringController:getState',
@@ -4689,7 +4902,7 @@ describe('AccountsController', () => {
           mockGetKeyringByType.mockReturnValueOnce([]),
         );
 
-        const { accountsController } = setupAccountsController({
+        setupAccountsController({
           initialState: {
             internalAccounts: {
               accounts: { [mockAccount.id]: mockAccount },
@@ -4702,8 +4915,15 @@ describe('AccountsController', () => {
           messenger,
         });
 
-        await messenger.call('AccountsController:updateAccounts');
-        expect(accountsController.updateAccounts).toHaveBeenCalledWith();
+        const initializedListener = jest.fn();
+        messenger.subscribe(
+          'AccountsController:initialized',
+          initializedListener,
+        );
+
+        messenger.call('AccountsController:init');
+
+        expect(initializedListener).toHaveBeenCalledTimes(1);
       });
     });
 
diff --git a/packages/accounts-controller/src/AccountsController.ts b/packages/accounts-controller/src/AccountsController.ts
index 50af609db83..845c41149ed 100644
--- a/packages/accounts-controller/src/AccountsController.ts
+++ b/packages/accounts-controller/src/AccountsController.ts
@@ -94,7 +94,7 @@ const MESSENGER_EXPOSED_METHODS = [
   'setAccountNameAndSelectAccount',
   'listAccounts',
   'listMultichainAccounts',
-  'updateAccounts',
+  'init',
   'getSelectedAccount',
   'getSelectedMultichainAccount',
   'getAccountByAddress',
@@ -212,6 +212,16 @@ export type AccountsControllerAccountAssetListUpdatedEvent = {
   payload: SnapKeyringAccountAssetListUpdatedEvent['payload'];
 };
 
+export type AccountsControllerInitializedEvent = {
+  type: `${typeof controllerName}:initialized`;
+  payload: [AccountsControllerState];
+};
+
+export type AccountsControllerUninitializedEvent = {
+  type: `${typeof controllerName}:uninitialized`;
+  payload: [];
+};
+
 /**
  * @deprecated This type is deprecated and will be removed in a future version.
  * Use `AccountTreeController`, `MultichainAccountService`, or the Keyring API v2 instead.
@@ -238,7 +248,9 @@ export type AccountsControllerEvents =
   | AccountsControllerAccountRenamedEvent
   | AccountsControllerAccountBalancesUpdatesEvent
   | AccountsControllerAccountTransactionsUpdatedEvent
-  | AccountsControllerAccountAssetListUpdatedEvent;
+  | AccountsControllerAccountAssetListUpdatedEvent
+  | AccountsControllerInitializedEvent
+  | AccountsControllerUninitializedEvent;
 
 /**
  * @deprecated This type is deprecated and will be removed in a future version.
@@ -330,6 +342,8 @@ export class AccountsController extends BaseController<
   AccountsControllerState,
   AccountsControllerMessenger
 > {
+  #initialized = false;
+
   /**
    * Constructor for AccountsController.
    *
@@ -662,14 +676,48 @@ export class AccountsController extends BaseController<
   }
 
   /**
-   * Updates the internal accounts list by retrieving normal and snap accounts,
-   * removing duplicates, and updating the metadata of each account.
+   * Initializes the controller by loading accounts from the current keyring
+   * state. Any accounts present in the keyrings but missing from the
+   * controller's state are added; existing accounts are preserved.
+   *
+   * Intended to be called after {@link clearState} to restore accounts from
+   * the keyrings (i.e. `clearState` then `init`), or on first startup.
    *
    * @deprecated This method is deprecated and will be removed in a future version.
    * Use `AccountTreeController`, `MultichainAccountService`, or the Keyring API v2 instead.
-   * @returns A Promise that resolves when the accounts have been updated.
    */
-  async updateAccounts(): Promise<void> {
+  init(): void {
+    if (this.#initialized) {
+      return;
+    }
+
+    const previousAccounts = this.state.internalAccounts.accounts;
+    this.#sync();
+
+    const addedAccounts = Object.values(
+      this.state.internalAccounts.accounts,
+    ).filter((account) => !previousAccounts[account.id]);
+
+    const removedAccountIds = Object.keys(previousAccounts).filter(
+      (id) => !this.state.internalAccounts.accounts[id],
+    );
+
+    if (addedAccounts.length > 0) {
+      this.messenger.publish('AccountsController:accountsAdded', addedAccounts);
+    }
+
+    if (removedAccountIds.length > 0) {
+      this.messenger.publish(
+        'AccountsController:accountsRemoved',
+        removedAccountIds,
+      );
+    }
+
+    this.#initialized = true;
+    this.messenger.publish('AccountsController:initialized', this.state);
+  }
+
+  #sync(): void {
     log('Synchronizing accounts with keyrings...');
 
     const keyringAccountIndexes = new Map<string, number>();
@@ -763,9 +811,11 @@ export class AccountsController extends BaseController<
    * Use `AccountTreeController`, `MultichainAccountService`, or the Keyring API v2 instead.
    */
   clearState(): void {
+    this.#initialized = false;
     this.update(() => {
       return getDefaultAccountsControllerState();
     });
+    this.messenger.publish('AccountsController:uninitialized');
   }
 
   /**
diff --git a/packages/accounts-controller/src/index.ts b/packages/accounts-controller/src/index.ts
index 5907b8ef207..79fa685f920 100644
--- a/packages/accounts-controller/src/index.ts
+++ b/packages/accounts-controller/src/index.ts
@@ -15,6 +15,8 @@ export type {
   AccountsControllerAccountBalancesUpdatesEvent,
   AccountsControllerAccountTransactionsUpdatedEvent,
   AccountsControllerAccountAssetListUpdatedEvent,
+  AccountsControllerInitializedEvent,
+  AccountsControllerUninitializedEvent,
   AllowedEvents,
   AccountsControllerEvents,
   AccountsControllerMessenger,
@@ -31,7 +33,7 @@ export type {
   AccountsControllerSetAccountNameAction,
   AccountsControllerSetAccountNameAndSelectAccountAction,
   AccountsControllerUpdateAccountMetadataAction,
-  AccountsControllerUpdateAccountsAction,
+  AccountsControllerInitAction,
   AccountsControllerLoadBackupAction,
   AccountsControllerClearStateAction,
 } from './AccountsController-method-action-types.js';
diff --git a/packages/wallet/src/Wallet.test.ts b/packages/wallet/src/Wallet.test.ts
index 2ffc6db1922..f84cf54d468 100644
--- a/packages/wallet/src/Wallet.test.ts
+++ b/packages/wallet/src/Wallet.test.ts
@@ -173,7 +173,7 @@ describe('Wallet', () => {
 
     const results = await wallet.init();
 
-    expect(results).toHaveLength(6);
+    expect(results).toHaveLength(7);
   });
 
   it('disallows modifying the messenger', async () => {