He was born on 25 July 1904 in
Gatehouse of Fleet in
Kirkcudbrightshire, the son of a butcher and farmer of a
smallholding. He was educated at Girthon School by William Learmonth, father of
James Learmonth who encouraged him to enter
Kirkcudbright Academy where he became school
dux. He then studied medicine at the
University of Edinburgh graduating MB ChB in 1927 and then became an Ettles Scholar and assistant to
Sir Stanley Davidson. In 1932 he went to London as a Beit Memorial Fellow at University College Hospital, working with
Sir Thomas Lewis and John McNee. He returned to Edinburgh in 1934 and specialised in
cardiology. In 1936 he was elected a Fellow of the
Royal Society of Edinburgh. His proposers were
Ivan De Burgh Daly,
Philip Eggleton,
Alfred Joseph Clark, and
David Murray Lyon. He resigned in 1957. In 1939 he was invited to Hammersmith by Prof Francis Fraser to the new school of medicine in Hammersmith in London. McMichael became its Director in 1946 and remained in the post for 20 years. He was knighted by Queen
Elizabeth II for services to medicine in 1965. He retired in 1966. He died in
Oxford on 4 March 1993. ==Family==