diff --git a/.changeset/clear-beds-refuse.md b/.changeset/clear-beds-refuse.md
new file mode 100644
index 0000000..24316cb
--- /dev/null
+++ b/.changeset/clear-beds-refuse.md
@@ -0,0 +1,5 @@
+---
+"react-polymorphic": patch
+---
+
+Fix `Inherit` required-prop behavior to preserve inherited `undefined` unions when converting optional inherited props to required.
diff --git a/package.json b/package.json
index 550641d..81e2c78 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
 	"name": "react-polymorphic",
-	"version": "1.0.1",
+	"version": "1.0.2",
 	"description": "Create polymorphic React 19+ components with strong TypeScript inference.",
 	"keywords": [
 		"react",
diff --git a/src/createPolymorph.ts b/src/createPolymorph.ts
index b3a52ae..1cd9a70 100644
--- a/src/createPolymorph.ts
+++ b/src/createPolymorph.ts
@@ -76,7 +76,7 @@ type RequiredKeys<T> = {
 /** Sets all keys in `K` of type `T` to required. */
 type Require<T, K extends PropertyKey> = Overwrite<
 	T,
-	Required<Pick<T, K extends keyof T ? K : never>>
+	{ [P in Extract<K, keyof T>]: T[P] }
 >;
 
 // Tag ------------------------------------------------------------------------
diff --git a/tests/integrations/createPolymorph/config.test.tsx b/tests/integrations/createPolymorph/config.test.tsx
index 6d34ff7..db06001 100644
--- a/tests/integrations/createPolymorph/config.test.tsx
+++ b/tests/integrations/createPolymorph/config.test.tsx
@@ -40,7 +40,7 @@ const ComponentE = createPolymorph<
 >(({ as: Tag = 'div', className, ...rest }) => {
 	return (
 		<Tag
-			className={typeof className === 'string' ? className : className()}
+			className={typeof className === 'function' ? className() : className}
 			{...rest}
 		/>
 	);
diff --git a/tests/types/createPolymorph/Inherit.test.tsx b/tests/types/createPolymorph/Inherit.test.tsx
index b738c89..71885c4 100644
--- a/tests/types/createPolymorph/Inherit.test.tsx
+++ b/tests/types/createPolymorph/Inherit.test.tsx
@@ -36,5 +36,6 @@ type _ = [
 			true
 		>
 	>,
+	Assert<IsEqual<P['onClick'], ComponentProps<'button'>['onClick']>>,
 	Assert<IsEqual<IsOptionalKey<P, 'onClick'>, false>>
 ];