Sir Michael was born in Wellington, the elder son of Justice Reginald Hardie Boys and Edith May (Bennett) Hardie Boys. After attending Hataitai School and Wellington College, he went on to Victoria University College, and gained a BA and an LLB degree. In December 1997, the University conferred on him the degree of Doctor of Laws (honoris causa). He has been a Visiting Fellow at Wolfson College, Cambridge, and in 1995 was elected an Honorary Fellow of that College.
Sir Michael married Mary Zohrab in 1957, and they have four children (two daughters, two sons) and several grandchildren.
Sir Michael had a distinguished career in law and practised in Wellington, before being appointed a High Court Judge in 1980. He was appointed to the Court of Appeal and became a Privy Counsellor in 1989. In 1994, he was elected an Honorary Bencher of Gray's Inn, London. He was a Council member of the Wellington District Law Society (1973-79) and President (1979) and a Council member of the New Zealand Law Society (1976-79). He was also a member of the Legal Aid Board (1974-80) and its Chairman (1978-80).
As a young man, Sir Michael was active in youth leadership in the Methodist and Anglican Churches and the Boys' Brigade. He has also been involved in a range of other community activities. For a number of years, he was a member of the Public and Social Affairs Committee of the Anglican Church, a member of the Management Committee and the Trust Board of Samuel Marsden Collegiate School and a member of the executive of the predecessor to the Independent Schools Association. He was also a Council member of the Automobile Association, Wellington (1978-80).
Sir Michael was knighted (GCMG) in 1995, received the first GNZM awarded in 1996, and is a Knight of the Order of St John. He was sworn in as New Zealand's 17th Governor-General on 21 March 1996. At the end of his term on 21 March 2001, he was awarded the Queen's Service Order for Public Services.