At his christening on 4 August 1942 in the Private Chapel of Windsor Castle, his godparents were: his paternal uncle the King; the Queen of the Netherlands (for whom her son-in-law Prince Bernhard stood proxy); the King of Norway (his great-uncle); US President Franklin D. Roosevelt (for whom the Duke of Kent stood proxy); the Hereditary Princess of Greece (who was not present), the wife of Paul of Greece, his first cousin-once-removed; the Duke of Gloucester (his paternal uncle, who was absent); the Dowager Marchioness of Milford Haven (his paternal first cousin twice-removed); and Lady Patricia Ramsay (his paternal first cousin twice-removed). Because of the war, newspaper reports did not identify the location of the christening and said instead that it took place at "a private chapel in the country". Just seven weeks after Michael's birth, his father was killed in a plane crash near Caithness, Scotland, on 25 August 1942.

Prince Michael entered the Royal Military Academy, Sandhurst, in January 1961, from where he was commissioned into the 11th Hussars (Prince Albert's Own), in 1963. He saw Service in Germany, Hong Kong, and Cyprus, where his squadron formed part of a United Nations peacekeeping force in 1971. Subsequent tours of duty, during a military career that spanned twenty years, included a number of appointments on the Defence Intelligence Staff. He retired from the Army with the rank of Major in 1981.

Prince Michael competed for Great Britain in the 1971 FIBT World Bobsleigh Championships but crashed and failed to finish the event. He was official non-travelling reserve for the 1972 Winter Olympics. He took part in the 1970 London to Mexico World Cup Rally in an Austin Maxi, but he and his crew failed to finish the event.

On 30 June 1978, Prince Michael was married, at a civil ceremony, at the Rathaus, Vienna, Austria, to Baroness Marie Christine von Reibnitz, the only daughter of the Silesian nobleman Baron Gunther Hubertus von Reibnitz and of his Austro-Hungarian wife, Maria Anna Carolina Franziska Walpurga Bernadette, Countess Szapáry de Muraszombath, Széchysziget et Szapár.

Prince Michael speaks fluent Russian and has a strong interest in Russia, where he is a well-known figure (he is a recipient of the Order of Friendship). Tsar Nicholas II was a first cousin of three of his grandparents. When the bodies of the Tsar and some of his family were recovered in 1991, the remains were later identified by DNA using, among others, a sample from Prince Michael for recognition. He attended the 1998 burial of the Tsar and his family in St Petersburg. He is an Honorary Member of the Romanov Family Association. He is also the second cousin of Maria Vladimirovna, Grand Duchess of Russia, who is a claimant to the headship of the Imperial Family of Russia. They share the same great-grandfather, Grand Duke Vladimir Alexandrovich.

Prince Michael has been under close scrutiny by the media for financial assistance given to him by Russian oligarch Boris Berezovsky. In May 2012, The Sunday Times reported that the Prince had received £320,000 during a six-year period from 2002 to 2008 into a family Business owned by the prince's secretary, from a fund controlled by Berezovsky, in which 56 payments of between £5,000 and £15,000 were sent through offshore companies. In an interview with The Sunday Times Berezovsky stated, "There is nothing underhand or improper about the financial assistance I have given Prince Michael. It is a matter between friends."

At the time of the marriage, Marie Christine von Reibnitz was not only a Roman Catholic, but also a divorcée. She had previously been married to the banker Thomas Troubridge; they separated in 1973, divorced in 1977, and had their marriage annulled by the Roman Catholic Church a year later, two months before her marriage to Prince Michael. Under the terms of the Act of Settlement 1701, Prince Michael forfeited his place in the line of succession to the throne through his marriage to a Roman Catholic. He was reinstated to the line of succession on 26 March 2015 with the coming into force of the Succession to the Crown Act 2013, and is now 45th in line to the throne.