James Sikking , who starred as a hardened police lieutenant on Hill Street Blues and as the titular character’s kindhearted dad on Doogie Howser, M.D. , has died at 90.

Sikking died of complications from dementia, his publicist Cynthia Snyder said in a statement Sunday evening. Born the youngest of five children on March 5, 1934, in Los Angeles, his early acting ventures included an uncredited part in Roger Corman’s Five Guns West and a bit role in an episode of Perry Mason . He also secured guest spots in a litany of popular 1970s television series, from the action-packed Mission: Impossible , M.

A.S.H.

, The F.B.I.

, The Rockford Files , Hawaii Five-O and Charlie’s Angels to Eight is Enough and Little House on the Prairie. Hill Street Blues would debut in 1981, a fresh take on the traditional police procedural. Sikking played Lieutenant Howard Hunter, a clean-cut Vietnam War veteran who headed the Emergency Action Team of the Metropolitan Police Department in a never-named city.

Story continues below advertisement View image in full screen James Sikking in ‘Hill Street Blues,’ Episode 2 “A Case of Klapp.” Robert Isenberg/NBCU Photo Bank/NBCUniversal via Getty Images via Getty Images The acclaimed show was a drama, but Sikking’s character’s uptight nature and quirks were often used to comic effect. Sikking based his performance on a drill instructor he’d had at basic training when military service cut through his time at the University of California, L.

A., .