The 41-year-old "Grey's Anatomy" star competed in the timed 2.5-hour Grand-Am Koni Challenge GS sports car race on Sunday. Dempsey is a driver and part-owner in the pro-Am sports car series.
Dempsey and co-driver Charles Espenlaub of Tampa finished sixth of 39 cars. It marked Dempsey's best finish in five Koni Challenge races.
Maneuvering a sports car and going as fast as 170 mph give him more of a rush than filming dramatic scenes for his television show, Dempsey said.
"I really enjoy racing much more than I enjoy doing the show," Dempsey said. "I mean I enjoy the show, but it's a different thing because it's like a long distance race."