The agency won the £4 million business after a competitive pitch against 13 undisclosed agencies. The media account was previously handled by Carat, while JJ Advertising and Libertine London shared the creative business.
GyroHSR will now be responsible for advertising, digital, media and CRM. A campaign for Heathrow Express will launch with a digital billboard that lets commuters travelling to the airport know about the latest travel news on the roads and the Tube.
Heathrow Express kicked off the pitch process in November by issuing shortlisted agencies with a one-line brief to "deliver a creative solution which will drive increased revenues".
The global account will be headed by GyroHSR's chief operating officer, Richard Perry. He said: "Working with a globally recognised brand such as Heathrow Express to ignite its already well-established international reputation is exactly the type of challenge we love."