The actor, running to raise money for the Maasai Wilderness Conservation Trust, finished in an impressive three hours, 48 minutes and one second - ahead of former E.R. star Anthony Edwards, who trotted home in four hours, eight minutes, and 20 seconds.
Christopher Reeve's son Matthew came in joint third in the showbiz race, crossing the line side by side with Strokes rocker Nikolai Fraiture after four hours, 23 minutes and 36 seconds. Reeve ran for his late father's charity foundation, while Fraiture raised money for a kids' cause.
Alanis Morrisette brought up the rear, finishing just five minutes later, clocking a time of four hours, 28 minutes and 45 seconds - also raising cash for the Maasai Wilderness Conservation Trust.
Illusionist David Blaine and actress Teri Hatcher were expected to join their showbiz pals in the starting line-up, but pulled out ahead of the race - Blaine for unknown reasons, and Hatcher after coming down with laryngitis.