Pinnow began his acting career on stage and has been active in German film and television since the 1970s. He was familiar in made-for-television plays and movies and in episodes of Tatort, Der Hausgeist, and the monkey sitcom Unser Charly. He was a regular on the family drama Die Wicherts von nebenan as Alwin Barthold and more recently appeared in the 2009 film Dinosaurier, a caper comedy about senior citizens. His voice has been heard on German radio, in audio dramas on records and cassettes, and in dubbing (including the cartoon Alfred J. Kwak).