The American actor James B Sikking, who has died aged 90, estimated that he had spent two-thirds of his career out of work before making a global impact as Lt Howard Hunter in the groundbreaking 1980s television police series Hill Street Blues.

The trigger-happy cop with a military mentality was the commander of an emergency action team – dubbed EATers – in the inner-city area of an unnamed location. Sikking based his portrayal on an officer he had met during army service in North Carolina.

“The drill instructor looked like he had steel for hair,” he explained, “and his uniform had so much starch in it you knew it would sit in the corner when he took it off in the barracks. So when I started to play Howard, I picked out the way he should be dressed. It had to be a very military look.” Sikking said that, to maintain credibility, his performance as the former Marine and Vietnam war veteran drew a fine line between “maniacal” and “buffoon”, in the manner of “very high-style French farce”.

The actor appeared in all seven series (1981-87) of the police procedural created by the writer-producer Steven Bochco with Michael Kozoll and, memorably, with Mike Post’s poignant jazz-rock theme tune starting each episode. He was among a large ensemble cast that included Daniel Travanti as Captain Frank Furillo, in charge of the Hill Street Precinct, Bruce Weitz as the undercover detective Mick Belker, Betty Thomas as the capable Sergeant Lucy Bates, and Barbara Bosson as Frank’s ex-wife, Fay.

Viewers were slow to appreciate this new breed of police show combining melodrama, comedy and pathos, embracing the jargon of the station house and shot with hand-held cameras close to the action, which was heightened by fast-paced editing. Its first series was one of the lowest rating peak-time programmes screened across the US in 1981, but the NBC network commissioned a further run after it garnered critical acclaim and eight Emmy awards – it eventually won 26.

Hill Street Blues was credited with revolutionising the portrayal of the police on US television with its warts-and-all depiction of law enforcers and superior writing. A bungled attempt by the lonely Hunter to take his own life was acknowledged as a rare misfire.

Bochco created the character – initially a sergeant, but quickly elevated to lieutenant – specially for Sikking, who had been a friend since getting one-off roles in early dramas on which Bochco worked, including The Bold Ones: The New Doctors and the magazine empire saga The Name of the Game (both in 1971).

After Hill Street Blues ended, the by then much lauded producer cast Sikking as David Howser, the GP father of the teen prodigy title character (played by Neil Patrick Harris), in Doogie Howser, MD (1989-93) and then the precinct captain Stan Jonas in another police series, Brooklyn South (1997-98), focusing on uniformed New York officers.

Born in Los Angeles to Sue (nee Paxton) and Art Sikking, both Unity church ministers, James attended El Segundo high school, California, and did army service in the middle of his studies at the University of California, Los Angeles, before graduating with a BA in theatre arts in 1959.

Sikking spent seven years as a lifeguard and construction worker before turning professional as an actor. He broke through on screen with film roles as an assassin in Point Blank (1967), a CIA agent in Scorpio (1973) and with the part of Dr Jim Hobart, a surgeon with a drink problem, in the daytime TV soap General Hospital (from 1973 to 1976).

During his Hill Street Blues run, Sikking had a cameo as the stuffy, pompous Captain Styles in the movie Star Trek III: The Search for Spock (1984). His later film roles included the FBI director in The Pelican Brief (1993).

Television fame brought him a short-lived stage run in the West End of London as the monstrous Hollywood film studio boss Marcus Hoff, alongside Martin Shaw, in the Clifford Odets play The Big Knife (Albery theatre, 1987), which was axed after five weeks.

His first marriage, to Mary Blakeman (1953-56), ended in divorce. He is survived by his second wife, Florine (nee Caplan), whom he married in 1962, and their son, Andrew, and daughter, Emily.