Biography: ​From Wikipedia, the free encyclopedia.   Dennis Franz (born October 28, 1944) is an American actor best known for his role as Andy Sipowicz, a hard boiled police detective in the television series NYPD Blue. He previously appeared as Lt. Norman Buntz on Hill Street Blues, and earlier played Detective Benedetto, a corrupt cop also on HSB. Description above from the Wikipedia article Dennis Franz  licensed under CC-BY-SA, full list of contributors on Wikipedia.