On June 27, 2005, Tilly won a World Series of Poker bracelet (and $158,625) in the Ladies' No-Limit Texas hold 'em event, beating 600 other players. She followed up this accomplishment on September 1, 2005, by winning the third World Poker Tour Ladies Invitational Tournament held at the Bicycle Casino in Bell Gardens, a suburb of Los Angeles. Tilly has appeared in the GSN Poker Royale series. Tilly played in the Celebrity Poker Showdown which aired June 14, 2006, on Bravo. She came in third place after being beaten by Bravo's online poker champion Ida Siconolfi. She also participated in the Poker After Dark show.
In a television interview in 2005, Tilly stated that at that point in her career she was more interested in pursuing poker than acting. By December 2008, Tilly announced her retirement from poker as a career. In her monthly column in Bluff Magazine, she said: "I love poker but greatness in poker is an elusive dream. There are too many variants. Trying to find validation in poker is like trying to find a virgin in a whorehouse. I'm not giving up poker entirely – gambling is an addiction after all. I'm just going to treat it more like a hobby and less like a career."