Lowe made his debut at the Manchester Repertory Theatre in 1945, where he was paid £5 per week for twice-nightly performances. He worked with various repertory companies around the country and became known for his character roles, which included parts in the West End musicals Call Me Madam, Pal Joey and The Pajama Game. An early brief film role was as a reporter for Tit-Bits magazine, near the end of Kind Hearts and Coronets (1949). Lowe married Joan Cooper (1922–1989) on 10 January 1948. They had met in 1945 when she was his leading lady at the Manchester Repertory Theatre and they remained together until his death. Their son, Stephen Lowe, was born on 23 January 1953.

In 1968, Lowe was cast in his best remembered role, as Captain Mainwaring in the BBC sitcom Dad’s Army (1968–1977). His colleagues on the show later remarked that the role resembled him: pompous and bumbling. Lowe had a clause written into his contract, specifying that he would never have to lose his trousers. He also played Mainwaring’s drunken brother Barry Mainwaring, in the 1975 Christmas episode “My Brother and I”. Lowe and his character also surfaced in a radio version of Dad’s Army, a stage play and a feature-length film released in 1971. While Dad’s Army was not in production, Lowe appeared in plays at the National Theatre and the Royal Court Theatre. In 1968 Lowe was invited by Laurence Olivier to act at the National Theatre at the Old Vic and appeared in Somerset Maugham’s Home and Beauty in 1968 and later The Tempest in 1974 with John Gielgud.

While touring at coastal theatres with his wife, Lowe used his distinctive 1885 former steam yacht Amazon as a floating base. He bought Amazon as a houseboat in 1968 but realised her potential and took her back to sea in 1971; this unique vessel is still operating in the Mediterranean. The ship had a bar with a semicircular notch cut halfway along, to enable both the portly figure of Lowe and his wife to serve behind the bar at the same time, acting as hosts during the parties they threw on board.

In 1972 Lowe also recorded the novelty songs “How I Won The War” and “My Little Girl, My Little Boy”.

When Dad’s Army ended in 1977, Lowe remained in demand, taking starring roles in television comedies such as Bless Me, Father with Daniel Abineri (1978–1981), as the mischievous Catholic priest Father Charles Clement Duddleswell and in Potter (1979–80) as the busybody Redvers Potter. By now he was making many television commercials, but his later stage career mainly involved touring the provinces, appearing in plays and pantomimes with his wife, Joan.

In 1981 he reprised his role as Captain Mainwaring for the pilot episode of It Sticks Out Half a Mile, a radio sequel to Dad’s Army. At Christmas 1981 Lowe appeared in pantomime with his wife. His last film role was in Lindsay Anderson’s Britannia Hospital (1982). In January 1982 Richard Burton had his private aeroplane fly Lowe to film a cameo role in the television series Wagner, his last screen performance.

Like his wife, Lowe suffered from alcoholism. In his final years, Lowe’s alcoholism worsened and he was reduced to acting in pantomimes and touring theatre productions. Graham Lord’s biography recalls that by 1979, Lowe was suffering from major health problems but continued to drink increasing amounts of alcohol, sometimes passing out on stage or at dinner. He was also a heavy smoker and his weight ballooned. Lowe had long suffered from narcolepsy. On 14 April 1982, Lowe gave a live televised interview on Pebble Mill at One. Later the same day, he collapsed from the onset of a stroke in his dressing room at the Alexandra Theatre, Birmingham, before a performance of Home at Seven, in which he appeared with his wife Joan. He died in hospital early the following morning, aged 66.

He was cremated and his ashes were scattered at Sutton Coldfield Crematorium, following a sparsely attended funeral. Joan did not attend as she refused to miss a performance of Home at Seven and was appearing in Belfast at the time. A memorial service was held in May 1982 at St Martin-in-the-Fields, attended by his family, former colleagues and many friends. His last sitcom, A.J. Wentworth, B.A., with Lowe as a boys’ preparatory school master, was shown during July and August 1982.

Two biographies of Arthur Lowe have been published: Arthur Lowe – Dad’s Memory by his son Stephen, which was issued in 1997; and more recently, Arthur Lowe by Graham Lord in 2002. In 2000, The Unforgettable Arthur Lowe was part of The Unforgettable series of TV biographies of comedy performers.

Tom Cole wrote in the Radio Times: “There are few actors who charmed viewers both young and old with such ease, and fewer still who could be trusted with the task of bringing classic literary characters like Charles Pooter and A.J. Wentworth to life.” His national acclaim continued well after his death, with a statue of Lowe erected in the town of Thetford, where most of the location work for Dad’s Army was filmed. Lowe was respected and admired among colleagues, including Laurence Olivier and John Gielgud. His sudden death received a large number of tributes. Speaking in 2002 Paul Scofield described Lowe as “a rare talent” and a “seriously brilliant actor”.

After his death Arthur Lowe received many tributes from British actors. John Inman described Lowe as “a great actor” and John Le Mesurier did the same. Similar tributes were made by Jimmy Perry, who described him as “a very kind man and would go out of his way to help actors less fortunate than himself. His rich comic genius will be sadly missed”. Clive Dunn referred to Lowe as one of the greatest “comic actors” he had ever worked with. Graham Lord wrote, in his 2003 biography, that “almost every actor who worked with Arthur considered him to be outstanding”.

In December 2007, plans were unveiled for a statue of Lowe to be erected in Thetford, Norfolk, where the outside scenes for Dad’s Army were filmed.

In an interview for a Dad’s Army retrospective on BBC television in 2010, Lowe’s co-star, Clive Dunn, described him sitting at the bar in the evenings when they were filming on location, consuming a drink which Lowe named ‘Amazon’ after his yacht. Dunn described the drink as comprising “gin and ginger ale, with a single slice of cucumber”.

The statue was unveiled on 19 June 2010, by the writers of the series, Jimmy Perry and David Croft. The star has also had two blue plaques unveiled, one at Maida Vale and one at his birthplace in Hayfield, Derbyshire.