A twenty-year veteran of the NYPD, his first acting role was that of an armed guard in Knots Landing in 1991. The next year, he was hired as a main supporting character in every episode of the short lived, critically acclaimed Ben Stiller Show until its cancellation. He has since appeared in such programs as Diagnosis: Murder, Seinfeld, Everybody Loves Raymond, Brooklyn South and The West Wing. The only time that he has appeared in the opening credits was NYPD Blue when he joined the show on a regular basis for the second half of the eleventh season. Gibson had been a recurring character beforehand.