diff --git a/packages/plugin-legacy/src/index.ts b/packages/plugin-legacy/src/index.ts
index 9e1e8f134b6f64..5e954c1ba07eb1 100644
--- a/packages/plugin-legacy/src/index.ts
+++ b/packages/plugin-legacy/src/index.ts
@@ -337,6 +337,11 @@ function viteLegacyPlugin(options: Options = {}): Plugin[] {
           if (fileName.includes('[name]')) {
             // [name]-[hash].[format] -> [name]-legacy-[hash].[format]
             fileName = fileName.replace('[name]', '[name]-legacy')
+          } else if (fileName.includes('[hash]')) {
+            // custom[hash].[format] -> [name]-legacy[hash].[format]
+            // custom-[hash].[format] -> [name]-legacy-[hash].[format]
+            // custom.[hash].[format] -> [name]-legacy.[hash].[format]
+            fileName = fileName.replace(/[.-]?\[hash\]/, '-legacy$&')
           } else {
             // entry.js -> entry-legacy.js
             fileName = fileName.replace(/(.+)\.(.+)/, '$1-legacy.$2')
diff --git a/playground/legacy/__tests__/legacy.spec.ts b/playground/legacy/__tests__/legacy.spec.ts
index 59cdc5a3999504..cfa6615fdcb1f0 100644
--- a/playground/legacy/__tests__/legacy.spec.ts
+++ b/playground/legacy/__tests__/legacy.spec.ts
@@ -97,6 +97,13 @@ describe.runIf(isBuild)('build', () => {
     expect(manifest['../../vite/legacy-polyfills-legacy'].src).toBe(
       '../../vite/legacy-polyfills-legacy',
     )
+    expect(manifest['custom0-legacy.js'].file).toMatch(
+      /chunk-X-legacy.\w{8}.js/,
+    )
+    expect(manifest['custom1-legacy.js'].file).toMatch(
+      /chunk-X-legacy-\w{8}.js/,
+    )
+    expect(manifest['custom2-legacy.js'].file).toMatch(/chunk-X-legacy\w{8}.js/)
     // modern polyfill
     expect(manifest['../../vite/legacy-polyfills']).toBeDefined()
     expect(manifest['../../vite/legacy-polyfills'].src).toBe(
diff --git a/playground/legacy/custom0.js b/playground/legacy/custom0.js
new file mode 100644
index 00000000000000..21ec276fc7f825
--- /dev/null
+++ b/playground/legacy/custom0.js
@@ -0,0 +1 @@
+export const foo = 'bar'
diff --git a/playground/legacy/custom1.js b/playground/legacy/custom1.js
new file mode 100644
index 00000000000000..21ec276fc7f825
--- /dev/null
+++ b/playground/legacy/custom1.js
@@ -0,0 +1 @@
+export const foo = 'bar'
diff --git a/playground/legacy/custom2.js b/playground/legacy/custom2.js
new file mode 100644
index 00000000000000..21ec276fc7f825
--- /dev/null
+++ b/playground/legacy/custom2.js
@@ -0,0 +1 @@
+export const foo = 'bar'
diff --git a/playground/legacy/main.js b/playground/legacy/main.js
index 7a42c3cf23a138..e34b5835c82b9d 100644
--- a/playground/legacy/main.js
+++ b/playground/legacy/main.js
@@ -3,6 +3,9 @@ import viteSvgPath from './vite.svg'
 import MyWorker from './worker?worker'
 
 async function run() {
+  await import('./custom0.js')
+  await import('./custom1.js')
+  await import('./custom2.js')
   const { fn } = await import('./async.js')
   fn()
 }
diff --git a/playground/legacy/vite.config.js b/playground/legacy/vite.config.js
index 3c4ec787809fee..4f319e250eb729 100644
--- a/playground/legacy/vite.config.js
+++ b/playground/legacy/vite.config.js
@@ -25,6 +25,10 @@ export default defineConfig({
         chunkFileNames(chunkInfo) {
           if (chunkInfo.name === 'immutable-chunk') {
             return `assets/${chunkInfo.name}.js`
+          } else if (/custom\d/.test(chunkInfo.name)) {
+            return `assets/chunk-X${
+              ['.', '-', ''][/custom(\d)/.exec(chunkInfo.name)[1]]
+            }[hash].js`
           }
           return `assets/chunk-[name].[hash].js`
         },