Dennis Dirk Blocker (born July 31, 1957) is an American actor and the son of late actor Dan Blocker, of the popular TV series, Bonanza and Dolphia Blocker (née Parker).
Dirk Blocker began appearing in American television in 1974, acting in an episode of Marcus Welby, M.D. at the age of sixteen. 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*, Quantum Leap and CHiPs.
Blocker was a regular on Baa Baa Black Sheep as one of the main pilots. He currently appears as Detective Hitchcock, a recurring character on Brooklyn Nine-Nine.
He has also appeared in such films and TV shows as Short Cuts, Poltergeist, Pink Cadillac, Mad City, Trouble in Mind, Midnight Madness, M*A*S*H, Doogie Howser, M.D., Matlock, and Prince of Darkness.