Harry Morgan: Actor best known as Colonel Potter in 'M*A*S*H'

The weasel-faced American actor Harry Morgan first came to the attention of audiences worldwide when he played Jack Webb's final sidekick, Officer Bill Gannon, in the gritty crime series Dragnet, which drew its storylines from cases actually investigated by the Los Angeles Police Department. The character was businesslike on duty but presented light relief at other times, sometimes seen displaying his questionable gourmet talents – such as making a garlic-nut-butter sandwich – and trying to persuade his boss, Sergeant Joe Friday (Webb), to give up his perpetual bachelorhood.

Morgan was chosen to play Gannon when Webb – who created and produced the drama, which ran for most of the 1950s – revived Dragnet in 1967 and Ben Alexander, who had played Officer Frank Smith in that earlier run, was held to contract by the producers of another police series. Morgan had previously appeared in films with Webb and took various roles in the radio version of Dragnet (1949-57).

However, he will be best remembered on television in the sitcom M*A*S*H as Colonel Sherman T Potter, the commanding officer trying to keep control of the American doctors and support staff of the 4077th Mobile Army Surgical Hospital unit during the Korean War. Although he could appear crusty, cantankerous and acerbic while dealing with the anarchic surgeon Hawkeye (Alan Alda), Margaret "Hot Lips" Houlihan and others, Potter was also sympathetic and a father figure to them. "He was firm," said Morgan in an interview for the Archive of American Television. "He was a good officer and had a good sense of humour. I think it's the best part I ever had." Morgan's portrayal was rewarded with a 1980 Emmy award as Outstanding Supporting Actor in a Comedy.

He had actually first appeared in M*A*S*H, based on Richard Hornberger's novel and the 1970 film, in 1974, when he played Major General Bartford Hamilton Steele, a demented officer visiting the unit. His performance impressed producers and earned Morgan an Emmy nomination. When McLean Stevenson, who played the commanding officer Colonel Henry Blake, left the programme the following year, Morgan was cast as Colonel Potter and brought a few personal touches to the role.

He placed a photograph of his then wife, Eileen Detchon, on the character's office desk and enjoyed scenes of the colonel looking after his horse, Sophie, because the actor raised quarter horses on a Santa Rosa ranch. Although several different horses were used on screen over the years, the one to whom he was seen saying goodbye in the final episode, in 1983, was his own.

He was born Harry Bratburg in Detroit, Michigan, during the First World War, the son of Scandinavian immigrants. He was a debating champion at Muskegon High School, Michigan, and started a law degree at the University of Chicago, where he gained some acting experience, but left when he could no longer afford to support himself. He then acted with the Civic Theatre company while selling office equipment in Washington, before joining a summer touring company. Still using his birth name, he made his Broadway début as Pepper White, alongside Elia Kazan, in the Clifford Odets drama Golden Boy (Belasco Theatre, 1937-8).

More Broadway roles followed, along with a film contract from 20th Century Fox when he moved to Hollywood and changed his professional name to Henry Morgan. His first appearance was in the US Marines drama To the Shores of Tripoli (1941), starring Randolph Scott. Dozens of character roles followed, often as bad guys and losers, including a drifter involved in a lynching in The Ox-Bow Incident (1943) and Charles Laughton's menacing bodyguard in The Big Clock (1948).

The turning point came in The Glenn Miller Story (1954) with his portrayal of Chummy MacGregor, the jazz musician's pianist, which led to more likeable roles. He then changed his name again, to Harry Morgan, to avoid being confused with the radio and television humorist Henry Morgan, and was cast in comedies such as John Goldfarb, Please Come Home! (1965), starring Shirley MacLaine and Peter Ustinov.

By then, he was also a prolific television actor. Alongside scores of one-off character roles, he was a regular as the henpecked neighbour Pete Porter in the sitcom December Bride (1954-59), who was spun off into his own series, Pete and Gladys (1960-62). Morgan also played the former jockey Seldom Jackson, assisting Dennis Weaver's widower and one-time horse trainer who becomes guardian to a 10-year-old boy, in Kentucky Jones (1964-66) and Doc Amos B Coogan, barber friend to Richard Boone's deputy sheriff of the title, in Hec Ramsey (1973-77).

He played Colonel Potter again, as chief of staff at a veterans' hospital, in the short-lived M*A*S*H post-war spin-off AfterMASH (1983-88) and had a cameo as Bill Gannon in the 1987 spoof Dragnet film starring Dan Aykroyd and Tom Hanks – as well as voicing the character in a 1995 episode of The Simpsons. Morgan retired four years later.

Anthony Hayward

Harry Bratburg (Harry Morgan), actor: born Detroit, Michigan 10 April 1915; married 1940 Eileen Detchon (died 1985; t hree sons, and one son deceased), 1986 Barbara Bushman; died Los Angeles 7 December 2011.