Blocker began appearing on American television in 1974, acting in an episode of Marcus Welby, M.D. at the age of 16. He has had guest roles in ER, Little House on the Prairie, The X-Files, Beverly Hills, 90210, Walker, Texas Ranger, Night Court, Murder, She Wrote, M*A*S*H, Doogie Howser, M.D., Matlock, Quantum Leap, and CHiPs. He was a regular on Baa Baa Black Sheep (1976–1978), playing pilot Jerry Bragg.