Gedrick was born in Chicago, Illinois. He began his career as an extra in films such as Bad Boys (1983) and Risky Business (1983). After roles in The Heavenly Kid (1985), Iron Eagle (1986), Promised Land (1987) with director Michael Hoffman, Iron Eagle II (1988 in an uncredited role for the first few minutes of the movie), Born on the Fourth of July (1989), cult classic Rooftops (1989), Backdraft (1991), and Crossing the Bridge (1992), Gedrick appeared in television series such as Class of '96 (1993) and Sweet Justice (1994).
In 1994, Gedrick starred in the film The Force with Yasmine Bleeth and Kim Delaney.
Gedrick's big break was in Steven Bochco's innovative 1995 series Murder One. The series followed the trial of Gedrick's character, bad-boy actor Neil Avedon, alleged to have murdered a 15-year-old girl. The series—which also starred such talent as Daniel Benzali, Patricia Clarkson, Mary McCormack, Dylan Baker, and Stanley Tucci—was a runaway success. Due to this, a second season was commissioned. Due to network concerns, the new season featured several small cases rather than one big one. Anthony LaPaglia stepped in to replace the cast such as Benzali, Tucci and Gedrick, who had left, and the series was canceled midway through its second season.
Gedrick's next major project was the three-hour TV film The Third Twin, a 1997 thriller based on the best-selling 1996 novel by British writer Ken Follett. Gedrick plays a university employee accused of rape, whose friend later discovers he has a twin—and actually several more twins cloned by an evil millionaire university donor and biomedical technology CEO (played to the hilt by Larry Hagman, a.k.a. Dallas ' J. R. Ewing).
Gedrick next took roles in television series such as EZ Streets (1996), Falcone (2000) and The Beast (2001). None of which were major successes. In 1999, he guest starred on Ally McBeal as the "hot car wash guy". Also appearing in Mario Puzo's 1997 miniseries, The Last Don and in its sequel, The Last Don II. Gedrick returned to television screens as Tom Turcotte in 2002's Boomtown. The series, which also starred Donnie Wahlberg and Neal McDonough was a moderate success, but ratings plummeted – particularly after the second season suffered a format change, and Boomtown was cancelled.
In 2003, Gedrick played Andrew Luster, the infamous rapist in a Lifetime movie based on his trial, A Date with Darkness. Gedrick was part of the cast of the 2006 NBC television series Windfall also starring Luke Perry and Gedrick's former Boomtown alumni, Lana Parrilla. In 2007, Gedrick again starred alongside Donnie Wahlberg in the A&E original movie Kings of South Beach. He was also the new love interest at Scavo's Pizzeria in Desperate Housewives in seasons 3 and 4 on ABC. In 2011, he appeared in Necessary Roughness as Dr. J. D. Aldridge, a former grad school professor and possible love interest for series lead Callie Thorne. Gedrick also starred in the 2006 movie Hidden Places alongside Sydney Penney and Shirley Jones, a film produced by Hallmark Entertainment.
Gedrick was a member of the cast of the HBO series Luck, which ran for one season in 2012. Gedrick appears in a multi-episode arc playing the manager of a Miami-area gentlemen’s club that becomes linked to a high-profile murder case in season 7 of Dexter. Beginning in November 2012, Gedrick starred as Evan Farnsworth, a struggling professor at a prestigious Maine boarding school, in the Hallmark film The Wishing Tree. In the fall of 2012, Gedrick appeared on an episode of NBC's Grimm.