Gatland is only the second person to receive the honour after Archbishop Sir David Moxon.
The 50-year-old former Ireland and Wasps coach was made an OBE in the Queen’s Birthday Honours last month and last December won Coach of the Year at the BBC Sports Personality Awards in London.
Gatland’s award, said Hamilton mayor Julie Hardaker, was to mark his ongoing contribution to rugby, locally and internationally.
“You have continued to make your mark on the rugby world stage, firstly as a coach for Ireland and since 2007 as coach for Wales – making you their longest-serving national coach,” she said.
“And all the while still maintaining a strong link to Hamilton and supporting our city on the international stage.”
