Ian Gillett Carmichael OBE (18 June 1920 – 5 February 2010) was an English actor who worked prolifically on stage, screen and radio in a career that spanned seventy years. Born in Kingston upon Hull, in the East Riding of Yorkshire, he trained at the Royal Academy of Dramatic Art, but his studies—and the early stages of his career—were curtailed by the Second World War. After his demobilisation he returned to acting and found success, initially in revue and sketch productions.

In 1955 Carmichael was noticed by the film producers John and Roy Boulting, who cast him in five of their films as one of the major players. The first was the 1956 film Private's Progress, a satire on the British Army; he received critical and popular praise for the role, including from the American market. In many of his roles he played a likeable, often accident-prone, innocent. In the mid-1960s he played Bertie Wooster in adaptations of the works of P. G. Wodehouse in The World of Wooster for BBC Television, for which he received mostly positive reviews, including from Wodehouse. In the early 1970s he played another upper-class literary character, Lord Peter Wimsey, the amateur but talented investigator created by Dorothy L. Sayers.

Much of Carmichael's success came through a disciplined approach to training and rehearsing for a role. He learned much about the craft and technique of humour while appearing with the comic actor Leo Franklyn. Although Carmichael tired of being typecast as the affable but bumbling upper-class Englishman, his craft ensured that while audiences laughed at his antics, he retained their affection; Dennis Barker, in Carmichael's obituary in The Guardian, wrote that he "could play fool parts in a way that did not cut the characters completely off from human sympathy: a certain dignity was always maintained".

Ian Gillett Carmichael was born on 18 June 1920 in Kingston upon Hull, in the East Riding of Yorkshire. He was the eldest child of Kate (née Gillett) and her husband Arthur Denholm Carmichael, an optician on the premises of his family's firm of jewellers. Carmichael had two younger sisters, the twins Mary and Margaret, who were born in December 1923. Robert Fairclough, his biographer, describes Carmichael's upbringing as a "privileged, pampered existence"; his parents employed maids and a cook. His infant education included one term at the local Froebel House School when he was four, but this was curtailed after his parents were shocked at the "alarmingly foul language he began bringing home", according to Alex Jennings, Carmichael's biographer in the Oxford Dictionary of National Biography.

In 1928 Carmichael was sent to Scarborough College, a prep school in North Yorkshire, which he attended between the ages of seven and thirteen. He did not like the spartan and authoritarian regime at the school. He described the discipline as "Dickensian", with corporal punishment used for even minor infringements of the rules; ablutions in the morning and evening were conducted with cold water—which often had a film of ice on the top during winter.

In 1933 Carmichael left Scarborough College and entered Bromsgrove School, a public school in Worcestershire. He soon concluded that "the new curriculum was not arduous", which gave him the opportunity to focus on matters that were of more interest for him: acting, popular music and cricket. In the late 1930s Carmichael decided to go to the Royal Academy of Dramatic Art (RADA) in London. His parents would have preferred he went into the family jewellery business, but accepted their son's decision and supported him financially when he left Yorkshire for London in January 1939.

Carmichael enjoyed his time at RADA, including the fact that women outnumbered men on his course, which he described as "heady stuff" after his boys-only boarding school. He remembered the time at RADA in the late 1930s fondly in his autobiography, describing it as:

A period of unconfined joy, occasioned by my finally shaking off the shackles of school discipline and being able to mix daily with young men and young women who shared my interests and enthusiasms. This joy was, nevertheless, being tempered by the worsening European situation. The fear that now, just as I was standing on the threshold of a future that I had dreamed about for years, the whole thing might be snuffed out like a candle was too unbearable to contemplate.