Gieb started his acting career in the late '70s with appearances in the horror film The Manitou (1978, along Michael Ansara and Felix Silla) and the television series Supertrain (1979, starring Joey Aresco). Throughout the '80s, Gieb had supporting roles in the comedy Under the Rainbow (1981, with Patty Maloney, Jim Boeke, Felix Silla, and Dennis Tracy), the science fiction comedy Weird Science (1985, with Robert Rusler, Michael Berryman, and Wallace Langham), the television horror comedy The Midnight Hour (1985, with LeVar Burton, Kurtwood Smith, Mickey Morton, and Scott L. Treger), and the comedy Going Overboard (1989, with Tom Hodges), and in television series such as Gimme a Break! (1984, with John Hoyt), Fame (1986, with Bebe Neuwirth), and was a regular on the comedy series Short Rib