Born in Hull, Yorkshire. He was educated at Scarborough College and Bromsgrove School. He made his name playing the sheltered innocent in a world of crooks and shirkers in a series of classic films for the Boulting Brothers, including Private's Progress (1956), Brothers in Law (1957) and I'm All Right Jack (1959), as well as similar films for other producers like School for Scoundrels (1960).

During the 1960s and 1970s, he enjoyed success in television, including the sitcom, Bachelor Father, based on the story of a real-life bachelor who took on several foster children. On television he enjoyed great popularity as Bertie Wooster, opposite Dennis Price as Jeeves, in several series of The World of Wooster, based on the works of P. G. Wodehouse. In later years, he was heard on BBC radio as Galahad Threepwood, another Wodehouse creation. In the 1970s, he memorably played Lord Peter Wimsey in several drama series based on the mystery novels by Dorothy L. Sayers. He appeared on television, notably in the ITV series, The Royal as the Hospital Secretary T.J. Middleditch (2003-2006). In 1999, he appeared in the BBC mini series Wives and Daughters. He was awarded an OBE in the 2003 New Year's Honours List.

Ian Carmichael has been married twice.