Bamman was born in Independence, Kansas, the son of Mary M. (née Farrell) and Harry W. Bamman, who worked in sales. Bamman was married to writer and director Emily Mann, but is now divorced from her. They have a son together named Nicholas. He is a graduate of St. Francis de Sales High School in Toledo, Ohio.
Lost in New York, his best-known roles. Bamman appeared as defense attorney Stan Gillum in several episodes of Law & Order and Law & Order SVU. Bamman was also in the first-season episode "The Blue Wall" playing Lt. Kennedy of Internal Affairs. Bamman co-starred in Runaway Jury as the blind jury foreman Herman Grimes. Bamman also played Dr. Judalon in the 1992 film Lorenzo's Oil.