Crawford was born Michael Patrick Dumbell-Smith in Salisbury, Wiltshire, England. He was raised by his widowed mother, Doris, and her parents, Montague Pike and Edith Kathleen O'Keefe, whom Crawford always called "Monty" and "Nan".

Doris's first husband, Arthur Dumbell-Smith, had been killed during the Battle of Britain, less than a year after they married. Two years after his death, Crawford was born, the result of a short-lived relationship, and given his mother's first husband's surname.

During his early years, he divided his time between the army camp in Wiltshire, where he and his mother were living during the war, and the Isle of Sheppey in Kent, where he also lived with his mother and grandparents. However, at the end of the war in 1945, his mother re-married a grocer named Den Ingram in 1945 and they moved to London. There Crawford attended Oakfield Preparatory School, Dulwich, where he was known as Michael Ingram.

He has won critical acclaim and numerous awards during his career, which includes radio, television and stage (including appearing on stage in the West End in London, and on Broadway in New York).

Although he most often appears on stage, in musicals such as The Phantom of the Opera and Barnum, he first became a household name and famous to millions for his role as the hapless Frank Spencer on the British television sitcom Some Mothers Do 'Ave 'Em (1973-78), for which he performed most of his own stunts.

The series became one of the BBC's most successful programmes of all time. Crawford has been appointed an Officer of the Order of the British Empire (OBE), and has also been named Showbusiness Personality of the Year by the Variety Club of Great Britain.