Dennis Dirk Blocker (born July 31, 1957) is an American actor and the son of actor Dan Blocker, of the popular TV series, Bonanza and Dolphia Lee Blocker (née Parker). He currently co-stars as Detective Hitchcock on the Fox comedy series Brooklyn Nine-Nine.

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; Doogie Howser, M.D.; Matlock; Quantum Leap; and CHiPs.

Blocker was a regular on Baa Baa Black Sheep (1976-78), playing pilot Jerry Bragg.

His film credits include Midnight Madness (1980), Raise the Titanic (1980), The Border (1982), Poltergeist (1982), Starman (1984), Trouble in Mind (1985), Made in Heaven (1987), Prince of Darkness (1987), Pink Cadillac (1989), Cutting Class (1989), Equinox (1993), Short Cuts (1993), Night of the Scarecrow (1995), and Mad City (1997).

[ Source: Wikipedia ]