Joan Reynolds and Leslie Randall in The Randall Touch, a 1958 sequel to their original series, Joan and Leslie.
Joan Reynolds, who has died aged 85, was the star of Joan and Leslie, the first home-grown sitcom on the newly launched commercial television channel ITV in 1955. It was immensely popular with viewers and helped to revive the sitcom on British television – the BBC had, after the second world war, launched Pinwright's Progress, then dropped it, and had only recently transferred Life With the Lyons from radio to television.
Reynolds and her actor husband, Leslie Randall, played a married couple. He was a journalist who wrote an agony-aunt column and she was a "resting" actor, performing the role of his stereotypical, dutiful wife. The programme, set in the fictional couple's London flat, began as Leslie Randall Entertains, then switched to the title Joan and Leslie towards the end of the first series, which consisted of 15-minute episodes. Two subsequent series were extended to 30 minutes and, by the final run, Reynolds and Randall were earning the then huge sum of £12,000 a year each. A sequel, The Randall Touch (1958), ran for 12 episodes.
Their fame kept the couple's profile high over the next decade, when they were regularly seen in commercials for the washing powder Fairy Snow (1962-67). An opportunity of success in Australia was dashed when Joan and Leslie was revived there in 1969, panned by the critics and achieved poor viewing figures. Following the couple's divorce in 1978, Reynolds never acted again.
Born in London, where her father was business manager of the Royal Opera House, Reynolds left Balham Central school for girls at the age of 14 to work as a draughtsman for the Coal Commission. A year later, she was devastated by the death of her father, from whom she gained a lifelong love of opera. Having enjoyed regular visits to the Old Vic theatre, watching Laurence Olivier, John Gielgud and Sybil Thorndike, Reynolds sought to switch careers and trained at the London Academy of Music and Dramatic Art.
She worked with the Osiris Players, Britain's first all-female professional company, touring in wagons pulled by two Rolls-Royces, then joined Darlington repertory company (1948-51), where she met Randall. They married in 1951. The couple toured together and performed on the radio show Henry Hall's Guest Night before TV fame. Both continued to be heard on the radio, then appeared as husband and wife in the film comedy Just Joe (1960) and a 1964 episode of the TV series Detective.
However, while Randall was cast in further film and TV roles, Reynolds never achieved solo success. She lived with him in the US when he appeared there on TV and in cabaret (1967-68). Then, they revived their screen partnership for the Australian version of Joan and Leslie.
In 1973 Reynolds became a medical secretary, first with the contact lens pioneer Jonathan Kersley, then at the Medical Research Council's social psychiatry unit, in London. In 1985 she retired and married Victor Herbert, with whom she enjoyed trips to opera productions. Herbert died earlier this year. Reynolds is survived by her daughter, Susan, and son, David, the children from her marriage to Randall.
• Joan Mary Reynolds, actor, born 18 February 1926; died 13 May 2011