Crean, who had a background in competitive fencing, began choreographing fights in 1932 when he was working in England as an actor in The Legends of Don Juan. He and his partner Rex Rickman were frequently hired to stage fight scenes for theatrical productions as well as in films such as The Master of Ballantrae (1953) and Sword of Sherwood Forest (1960). They both ran the Sophy School of Fencing in London and used it to teach many celebrities sword work for stage and films. He worked with actors including Paul Scofield, Laurence Olivier, Trevor Howard, Alec Guinness, Douglas Fairbanks Jr. and Errol Flynn, often performing as Flynn's stunt double in films.
Crean travelled to the Canadian Stratford Theatre Festival in 1962 to serve as the fight arranger for Macbeth, directed by Peter Coe. After his second season in 1963, he decided to make Stratford, Ontario his home and worked as the festival's fight director until 1983. Among festival productions for which he arranged the swordplay, The Three Musketeers, directed by John Hirsch in 1968, received great acclaim for its stage action. Crean returned from retirement in 1988 to assist fight director Jean-Pierre Fournier for The Three Musketeers as directed by Richard Ouzounian.
Crean's choreographic philosophy included tenets such as matching the combat to the character and included research into various historical and cultural forms of swordplay. His system of stage combat safety protocols were highly influential around the world. Those guidelines were codified through the Society of British Fight Directors, for which Crean was a fight master. He was also a certified fight master with Fight Directors Canada as well as being an honorary member of the Society of American Fight Directors.
Crean continued to work as an actor, sometimes taking small roles in shows for which he had done fight arranging and also performing his one-man show about Rudyard Kipling, The Sun Never Sets, at Stratford's Avon Theatre in 1970.
The annual Paddy Crean International Stage Combat Conferences, named in honour of Mr. Crean, present a wide range of seminars run by prominent stage combat and martial arts instructors.
Patrick Crean died on 22 December 2003, at the age of 93. He was married to the actress Helen Christie.