Born in Oklahoma, Porter was three when his father died in a road accident. Educated in his home state, as well as in Nebraska and Oregon, the 14- year-old Don joined the Oregon National Guard, claiming to be 18. By the time he actually was 18, he had been commissioned a lieutenant. He was by then a professional actor as well, having started playing dramatic parts at 17 on local radio. In 1936 he made his first stage appearance as a messenger in Maxwell Anderson's Elizabeth the Queen at the Civic Theatre in Portland.
After years in repertory, Porter made his first screen appearance in Mystery of the White Room (1939). After signing him for seven years, Universal Pictures proceeded to get their money's worth; in 1942 alone, their new contract artist appeared in Eagle Squadron, Top Sergeant, Madame Spy, Eyes of the Underworld, Night Monster, and as the killer in Abbott and Costello's mystery spoof Who Done It?
The Dead End Kids vehicle Keep 'Em Slugging (1943) was the last Don Porter film for three years. His hobby was photography, which, coupled with his military training, served him in good stead as a combat photographer during the Second World War. When he was discharged, he returned to Universal to play a lawyer whose fiancee (June Lockhart) mistakenly believed she was a werewolf in She- Wolf of London (1946), a movie that was far funnier than Abbott and Costello's Buck Privates Come Home (1947), the last film of Porter's Universal contract. Becoming a freelance, he went to Paramount for My Friend Irma Goes West (1950), to Columbia for 711 Ocean Drive (1950), to RKO for The Racket (1951), and to MGM for Because You're Mine (1952).
His face soon became internationally recognised, thanks to the television sitcom Private Secretary (1952-57). Ann Sothern starred as the super-efficient Susie MacNamara, whose life was dedicated to bringing order to her employer, the successful but disorganised talent agent, Peter Sands (Porter). The series finally ended after 104 episodes, but its co-stars were soon teamed again in The Ann Sothern Show (1958-61), which concerned Katy O'Connor, the super-efficient assistant manager of a New York hotel, and its disorganised manager, Mr Devery.
During the out-of-town tryouts of Muriel Resnick's play Any Wednesday (1964), Michael Rennie gave up the role of John Cleeves, an adulterous businessman, nakedly admitting he was leaving because his fellow actor Gene Hackman was "getting too many laughs". Porter had no such qualms; he accepted the role, and earned praise for his performance, playing Cleeves 982 times on Broadway. Taking over from George C. Scott in Neil Simon's triptych of one-act comedies Plaza Suite (1969), he successfully played a harassed father, a womanising film producer, and yet another adulterous businessman.
Porter interspersed stage appearances with such films as Mame (1974), Forty Carats (1973), Bob Hope's Bachelor in Paradise (1961) and Elvis Presley's Live a Little, Love a Little (1968), but in the 25 years since The Candidate he never again had a role as juicy as Senator Crocker Jarmon.
Donald Porter, actor: born Miami, Oklahoma 24 September 1912; married Peggy Converse (one son, one daughter); died Los Angeles 11 February 1997.