diff --git a/packages/@aws-cdk/aws-ecs/lib/base/task-definition.ts b/packages/@aws-cdk/aws-ecs/lib/base/task-definition.ts
index fe17ce6cb2317..1861098e1395b 100644
--- a/packages/@aws-cdk/aws-ecs/lib/base/task-definition.ts
+++ b/packages/@aws-cdk/aws-ecs/lib/base/task-definition.ts
@@ -647,7 +647,7 @@ export class TaskDefinition extends TaskDefinitionBase {
   /**
    * Returns the container that match the provided containerName.
    */
-  private findContainer(containerName: string): ContainerDefinition | undefined {
+  public findContainer(containerName: string): ContainerDefinition | undefined {
     return this.containers.find(c => c.containerName === containerName);
   }
 
diff --git a/packages/@aws-cdk/aws-stepfunctions-tasks/lib/ecs/run-task.ts b/packages/@aws-cdk/aws-stepfunctions-tasks/lib/ecs/run-task.ts
index b53b7cbab9dcf..496decc60c851 100644
--- a/packages/@aws-cdk/aws-stepfunctions-tasks/lib/ecs/run-task.ts
+++ b/packages/@aws-cdk/aws-stepfunctions-tasks/lib/ecs/run-task.ts
@@ -262,7 +262,7 @@ export class EcsRunTask extends sfn.TaskStateBase implements ec2.IConnectable {
     for (const override of this.props.containerOverrides ?? []) {
       const name = override.containerDefinition.containerName;
       if (!cdk.Token.isUnresolved(name)) {
-        const cont = this.props.taskDefinition.node.tryFindChild(name);
+        const cont = this.props.taskDefinition.findContainer(name);
         if (!cont) {
           throw new Error(`Overrides mention container with name '${name}', but no such container in task definition`);
         }
diff --git a/packages/@aws-cdk/aws-stepfunctions-tasks/test/ecs/run-tasks.test.ts b/packages/@aws-cdk/aws-stepfunctions-tasks/test/ecs/run-tasks.test.ts
index 947b5cb0c8986..8e93cdd6d0aab 100644
--- a/packages/@aws-cdk/aws-stepfunctions-tasks/test/ecs/run-tasks.test.ts
+++ b/packages/@aws-cdk/aws-stepfunctions-tasks/test/ecs/run-tasks.test.ts
@@ -48,6 +48,80 @@ test('Cannot create a Fargate task without a default container', () => {
   ).toThrowError(/must have at least one essential container/);
 });
 
+test('Cannot override container definitions when container is not in task definition', () => {
+  const taskDefinitionA = new ecs.TaskDefinition(stack, 'TaskDefinitionA', {
+    memoryMiB: '512',
+    cpu: '256',
+    compatibility: ecs.Compatibility.FARGATE,
+  });
+  taskDefinitionA.addContainer('TheContainerA', {
+    image: ecs.ContainerImage.fromRegistry('foo/bar'),
+    memoryLimitMiB: 256,
+  });
+
+  const taskDefinitionB = new ecs.TaskDefinition(stack, 'TaskDefinitionB', {
+    memoryMiB: '512',
+    cpu: '256',
+    compatibility: ecs.Compatibility.FARGATE,
+  });
+  const containerDefinitionB = taskDefinitionB.addContainer('TheContainerB', {
+    image: ecs.ContainerImage.fromRegistry('foo/bar'),
+    memoryLimitMiB: 256,
+  });
+
+  expect(() =>
+    new tasks.EcsRunTask(stack, 'task', {
+      cluster,
+      taskDefinition: taskDefinitionA,
+      containerOverrides: [
+        {
+          containerDefinition: containerDefinitionB,
+          environment: [{ name: 'SOME_KEY', value: sfn.JsonPath.stringAt('$.SomeKey') }],
+        },
+      ],
+      launchTarget: new tasks.EcsFargateLaunchTarget(),
+    }).toStateJson(),
+  ).toThrowError(/no such container in task definition/);
+});
+
+test('Running a task with container override and container has explicitly set a container name', () => {
+  const taskDefinition = new ecs.TaskDefinition(stack, 'TD', {
+    memoryMiB: '512',
+    cpu: '256',
+    compatibility: ecs.Compatibility.FARGATE,
+  });
+  const containerDefinition = taskDefinition.addContainer('TheContainer', {
+    containerName: 'ExplicitContainerName',
+    image: ecs.ContainerImage.fromRegistry('foo/bar'),
+    memoryLimitMiB: 256,
+  });
+
+  expect(stack.resolve(
+    new tasks.EcsRunTask(stack, 'task', {
+      cluster,
+      taskDefinition,
+      containerOverrides: [
+        {
+          containerDefinition,
+          environment: [{ name: 'SOME_KEY', value: sfn.JsonPath.stringAt('$.SomeKey') }],
+        },
+      ],
+      launchTarget: new tasks.EcsFargateLaunchTarget(),
+    }).toStateJson())).toHaveProperty('Parameters.Overrides', {
+    ContainerOverrides: [
+      {
+        Environment: [
+          {
+            Name: 'SOME_KEY',
+            'Value.$': '$.SomeKey',
+          },
+        ],
+        Name: 'ExplicitContainerName',
+      },
+    ],
+  });
+});
+
 test('Running a Fargate Task', () => {
   const taskDefinition = new ecs.TaskDefinition(stack, 'TD', {
     memoryMiB: '512',