diff --git a/index.js b/index.js
deleted file mode 100644
index 2960a9db62d76..0000000000000
--- a/index.js
+++ /dev/null
@@ -1,24 +0,0 @@
-/**
- * Copyright 2017 Google Inc. All rights reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-const { initializePuppeteer } = require('./lib/index');
-
-const puppeteer = initializePuppeteer({
-  packageJson: require('./package.json'),
-  rootDirectory: __dirname,
-});
-
-module.exports = puppeteer;
diff --git a/install.js b/install.js
index 13272b60ba297..cf56da410ea48 100644
--- a/install.js
+++ b/install.js
@@ -41,7 +41,7 @@ async function download() {
     process.env.PUPPETEER_DOWNLOAD_HOST ||
     process.env.npm_config_puppeteer_download_host ||
     process.env.npm_package_config_puppeteer_download_host;
-  const puppeteer = require('./index');
+  const puppeteer = require('.');
   const product =
     process.env.PUPPETEER_PRODUCT ||
     process.env.npm_config_puppeteer_product ||
diff --git a/package.json b/package.json
index 28569351a39d5..ba0d15dbe314d 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
   "name": "puppeteer",
   "version": "4.0.0-post",
   "description": "A high-level API to control headless Chrome over the DevTools Protocol",
-  "main": "index.js",
+  "main": "lib/index.js",
   "repository": "github:puppeteer/puppeteer",
   "engines": {
     "node": ">=10.18.1"
diff --git a/src/index.ts b/src/index.ts
index a083eacbcc79e..3df618f8c3874 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,5 +1,5 @@
 /**
- * Copyright 2020 Google Inc. All rights reserved.
+ * Copyright 2017 Google Inc. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,59 +14,21 @@
  * limitations under the License.
  */
 
-// api.ts has to use module.exports as it's also consumed by DocLint which runs
-// on Node.
-// eslint-disable-next-line @typescript-eslint/no-var-requires
-const api = require('./api');
+import { initializePuppeteer } from './initialize';
+import * as path from 'path';
 
-import { helper } from './common/helper';
-import { Page } from './common/Page';
-import { Puppeteer } from './common/Puppeteer';
+const puppeteer = initializePuppeteer({
+  packageJson: require(path.join(__dirname, '..', 'package.json')),
+  rootDirectory: path.join(__dirname, '..'),
+});
 
-interface InitOptions {
-  packageJson: {
-    puppeteer: {
-      chromium_revision: string;
-      firefox_revision: string;
-    };
-    name: string;
-  };
-  rootDirectory: string;
-}
-
-export const initializePuppeteer = (options: InitOptions): Puppeteer => {
-  const { packageJson, rootDirectory } = options;
-
-  for (const className in api) {
-    if (typeof api[className] === 'function')
-      helper.installAsyncStackHooks(api[className]);
-  }
-
-  // Expose alias for deprecated method.
-  // @ts-expect-error emulateMedia does not exist error
-  Page.prototype.emulateMedia = Page.prototype.emulateMediaType;
-
-  let preferredRevision = packageJson.puppeteer.chromium_revision;
-  const isPuppeteerCore = packageJson.name === 'puppeteer-core';
-  // puppeteer-core ignores environment variables
-  const product = isPuppeteerCore
-    ? undefined
-    : process.env.PUPPETEER_PRODUCT ||
-      process.env.npm_config_puppeteer_product ||
-      process.env.npm_package_config_puppeteer_product;
-  if (!isPuppeteerCore && product === 'firefox')
-    preferredRevision = packageJson.puppeteer.firefox_revision;
-
-  const puppeteer = new Puppeteer(
-    rootDirectory,
-    preferredRevision,
-    isPuppeteerCore,
-    product
-  );
-
-  // The introspection in `Helper.installAsyncStackHooks` references `Puppeteer._launcher`
-  // before the Puppeteer ctor is called, such that an invalid Launcher is selected at import,
-  // so we reset it.
-  puppeteer._lazyLauncher = undefined;
-  return puppeteer;
-};
+/*
+ * Has to be CJS here rather than ESM such that the output file ends with
+ * module.exports = puppeteer.
+ *
+ * If this was export default puppeteer the output would be:
+ * exports.default = puppeteer
+ * And therefore consuming via require('puppeteer') would break / require the user
+ * to access require('puppeteer').default;
+ */
+module.exports = puppeteer;
diff --git a/src/initialize.ts b/src/initialize.ts
new file mode 100644
index 0000000000000..a083eacbcc79e
--- /dev/null
+++ b/src/initialize.ts
@@ -0,0 +1,72 @@
+/**
+ * Copyright 2020 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// api.ts has to use module.exports as it's also consumed by DocLint which runs
+// on Node.
+// eslint-disable-next-line @typescript-eslint/no-var-requires
+const api = require('./api');
+
+import { helper } from './common/helper';
+import { Page } from './common/Page';
+import { Puppeteer } from './common/Puppeteer';
+
+interface InitOptions {
+  packageJson: {
+    puppeteer: {
+      chromium_revision: string;
+      firefox_revision: string;
+    };
+    name: string;
+  };
+  rootDirectory: string;
+}
+
+export const initializePuppeteer = (options: InitOptions): Puppeteer => {
+  const { packageJson, rootDirectory } = options;
+
+  for (const className in api) {
+    if (typeof api[className] === 'function')
+      helper.installAsyncStackHooks(api[className]);
+  }
+
+  // Expose alias for deprecated method.
+  // @ts-expect-error emulateMedia does not exist error
+  Page.prototype.emulateMedia = Page.prototype.emulateMediaType;
+
+  let preferredRevision = packageJson.puppeteer.chromium_revision;
+  const isPuppeteerCore = packageJson.name === 'puppeteer-core';
+  // puppeteer-core ignores environment variables
+  const product = isPuppeteerCore
+    ? undefined
+    : process.env.PUPPETEER_PRODUCT ||
+      process.env.npm_config_puppeteer_product ||
+      process.env.npm_package_config_puppeteer_product;
+  if (!isPuppeteerCore && product === 'firefox')
+    preferredRevision = packageJson.puppeteer.firefox_revision;
+
+  const puppeteer = new Puppeteer(
+    rootDirectory,
+    preferredRevision,
+    isPuppeteerCore,
+    product
+  );
+
+  // The introspection in `Helper.installAsyncStackHooks` references `Puppeteer._launcher`
+  // before the Puppeteer ctor is called, such that an invalid Launcher is selected at import,
+  // so we reset it.
+  puppeteer._lazyLauncher = undefined;
+  return puppeteer;
+};