 After two years on the sidelines, Summerton was signed to Rahal Letterman Lanigan Racing for the 2012 12 Hours of Sebring along with fellow BMW drivers Joey Hand and Dirk Müller in the GTLM class.Winning his first race the coveted 12 hours of Sebring in their class and 18th overall.Summerton set fastest race laps at 2 events along with finishing at Petit LeMans 3rd place.