diff --git a/packages/next/src/executors/server/custom-server.impl.ts b/packages/next/src/executors/server/custom-server.impl.ts
index e6ec5f795a94f..ea61f4b4cb34c 100644
--- a/packages/next/src/executors/server/custom-server.impl.ts
+++ b/packages/next/src/executors/server/custom-server.impl.ts
@@ -15,7 +15,8 @@ export default async function* serveExecutor(
     : 'production';
 
   // Setting port that the custom server should use.
-  (process.env as any).PORT = options.port;
+  process.env.PORT = options.port ? `${options.port}` : process.env.PORT;
+  options.port = parseInt(process.env.PORT);
 
   const projectRoot = context.projectGraph.nodes[context.projectName].data.root;
 
diff --git a/packages/next/src/executors/server/server.impl.ts b/packages/next/src/executors/server/server.impl.ts
index f770dfa245273..d87ffa469b25d 100644
--- a/packages/next/src/executors/server/server.impl.ts
+++ b/packages/next/src/executors/server/server.impl.ts
@@ -29,7 +29,7 @@ export default async function* serveExecutor(
   );
   const projectRoot = context.workspace.projects[context.projectName].root;
 
-  const { port, keepAliveTimeout, hostname } = options;
+  const { keepAliveTimeout, hostname } = options;
 
   // This is required for the default custom server to work. See the @nx/next:app generator.
   process.env.NX_NEXT_DIR = projectRoot;
@@ -42,9 +42,10 @@ export default async function* serveExecutor(
     : 'production';
 
   // Setting port that the custom server should use.
-  process.env.PORT = `${options.port}`;
+  process.env.PORT = options.port ? `${options.port}` : process.env.PORT;
+  options.port = parseInt(process.env.PORT);
 
-  const args = createCliOptions({ port, hostname });
+  const args = createCliOptions({ port: options.port, hostname });
 
   if (keepAliveTimeout && !options.dev) {
     args.push(`--keepAliveTimeout=${keepAliveTimeout}`);
@@ -81,11 +82,11 @@ export default async function* serveExecutor(
       process.on('SIGTERM', () => killServer());
       process.on('SIGHUP', () => killServer());
 
-      await waitForPortOpen(port, { host: options.hostname });
+      await waitForPortOpen(options.port, { host: options.hostname });
 
       next({
         success: true,
-        baseUrl: `http://${options.hostname ?? 'localhost'}:${port}`,
+        baseUrl: `http://${options.hostname ?? 'localhost'}:${options.port}`,
       });
     }
   );