diff --git a/packages/amplify-graphql-default-value-transformer/package.json b/packages/amplify-graphql-default-value-transformer/package.json
index 32bf38253d..9839b40476 100644
--- a/packages/amplify-graphql-default-value-transformer/package.json
+++ b/packages/amplify-graphql-default-value-transformer/package.json
@@ -75,7 +75,8 @@
       "src/**/*.ts"
     ],
     "coveragePathIgnorePatterns": [
-      "/__tests__/"
+      "/__tests__/",
+      "types.ts"
     ],
     "snapshotFormat": {
       "escapeString": true,
diff --git a/packages/amplify-graphql-default-value-transformer/src/__tests__/__snapshots__/amplify-grapphql-default-value-transformer.test.ts.snap b/packages/amplify-graphql-default-value-transformer/src/__tests__/__snapshots__/amplify-grapphql-default-value-transformer.test.ts.snap
index 320a27b4e9..d94e2aabac 100644
--- a/packages/amplify-graphql-default-value-transformer/src/__tests__/__snapshots__/amplify-grapphql-default-value-transformer.test.ts.snap
+++ b/packages/amplify-graphql-default-value-transformer/src/__tests__/__snapshots__/amplify-grapphql-default-value-transformer.test.ts.snap
@@ -189,7 +189,7 @@ input ModelTestConditionInput {
 
 input CreateTestInput {
   id: ID
-  stringValue: String!
+  stringValue: String
 }
 
 input UpdateTestInput {
diff --git a/packages/amplify-graphql-default-value-transformer/src/__tests__/amplify-grapphql-default-value-transformer.test.ts b/packages/amplify-graphql-default-value-transformer/src/__tests__/amplify-grapphql-default-value-transformer.test.ts
index 344b350d5f..8e76bf9a07 100644
--- a/packages/amplify-graphql-default-value-transformer/src/__tests__/amplify-grapphql-default-value-transformer.test.ts
+++ b/packages/amplify-graphql-default-value-transformer/src/__tests__/amplify-grapphql-default-value-transformer.test.ts
@@ -217,6 +217,54 @@ describe('DefaultValueModelTransformer:', () => {
     ).toThrow('Default value "text" is not a valid AWSIPAddress.');
   });
 
+  it('throws if @default is used on an implicit primaryKey', () => {
+    const schema = `
+      type Test @model {
+        id: ID! @default(value: "ID: 80361")
+        stringValue: String!
+      }
+    `;
+
+    expect(() =>
+      testTransform({
+        schema,
+        transformers: [new ModelTransformer(), new DefaultValueTransformer()],
+      }),
+    ).toThrow('The @default directive may not be applied to primaryKey fields.');
+  });
+
+  it('throws if @default is used on an explicit primaryKey', () => {
+    const schema = `
+      type Test @model {
+        id: ID! @default(value: "ID: 80361") @primaryKey
+        stringValue: String!
+      }
+    `;
+
+    expect(() =>
+      testTransform({
+        schema,
+        transformers: [new ModelTransformer(), new DefaultValueTransformer(), new PrimaryKeyTransformer()],
+      }),
+    ).toThrow('The @default directive may not be applied to primaryKey fields.');
+  });
+
+  it('throws if @default is used on a composite key member', () => {
+    const schema = `
+    type Project @model {
+      projectId: ID! @primaryKey(sortKeyFields: ["name"])
+      name: String! @default(value: "Mustapha Mond")
+    }
+    `;
+
+    expect(() =>
+      testTransform({
+        schema,
+        transformers: [new ModelTransformer(), new DefaultValueTransformer(), new PrimaryKeyTransformer()],
+      }),
+    ).toThrow('The @default directive may not be applied to composite key member fields.');
+  });
+
   it('should validate enum values', async () => {
     const inputSchema = `
       type Post @model {
diff --git a/packages/amplify-graphql-default-value-transformer/src/graphql-default-value-transformer.ts b/packages/amplify-graphql-default-value-transformer/src/graphql-default-value-transformer.ts
index 15c76e22a5..01fd4b424f 100644
--- a/packages/amplify-graphql-default-value-transformer/src/graphql-default-value-transformer.ts
+++ b/packages/amplify-graphql-default-value-transformer/src/graphql-default-value-transformer.ts
@@ -20,6 +20,7 @@ import {
   FieldDefinitionNode,
   InterfaceTypeDefinitionNode,
   Kind,
+  ListValueNode,
   ObjectTypeDefinitionNode,
   StringValueNode,
   TypeNode,
@@ -72,10 +73,34 @@ const validateDefaultValueType = (ctx: TransformerSchemaVisitStepContextProvider
   }
 };
 
+const validateNotPrimaryKey = (field: FieldDefinitionNode): void => {
+  const isPrimaryKeyField =
+    field.directives!.find((dir) => dir.name.value === 'primaryKey') ||
+    (getBaseType(field.type) === 'ID' && field.type.kind === Kind.NON_NULL_TYPE && field.name.value === 'id');
+
+  if (isPrimaryKeyField) {
+    throw new InvalidDirectiveError('The @default directive may not be applied to primaryKey fields.');
+  }
+};
+
+const validateNotCompositeKeyMember = (config: DefaultValueDirectiveConfiguration): void => {
+  const objectDirectives = config.object.fields?.flatMap((f) => f.directives);
+  const primaryKeyDirective = objectDirectives?.find((dir) => dir?.name.value === 'primaryKey');
+  if (primaryKeyDirective) {
+    const sortKeyFields = primaryKeyDirective.arguments?.find((arg) => arg.name.value === 'sortKeyFields')?.value as ListValueNode;
+    const sortKeys = sortKeyFields?.values as StringValueNode[];
+    if (sortKeys?.some((sortKey) => sortKey.value === config.field.name.value)) {
+      throw new InvalidDirectiveError('The @default directive may not be applied to composite key member fields.');
+    }
+  }
+};
+
 const validate = (ctx: TransformerSchemaVisitStepContextProvider, config: DefaultValueDirectiveConfiguration): void => {
   validateModelDirective(config);
   validateFieldType(ctx, config.field.type);
   validateDirectiveArguments(config.directive);
+  validateNotPrimaryKey(config.field);
+  validateNotCompositeKeyMember(config);
 
   // Validate the default values only for the DynamoDB datasource.
   // For SQL, the database determines and sets the default value. We will not validate the value in transformers.
@@ -123,6 +148,7 @@ export class DefaultValueTransformer extends TransformerPluginBase {
         const input = InputObjectDefinitionWrapper.fromObject(name, config.object, ctx.inputDocument);
         const fieldWrapper = input.fields.find((f) => f.name === config.field.name.value);
         fieldWrapper?.makeNullable();
+        ctx.output.updateInput(input.serialize());
       }
     }
   };