Michael O'Leary may refer to:Michael John O'Leary (1890–1961), Irish-Canadian recipient of the Victoria Cross Michael O'Leary (politician) (1936–2006), Irish politician and leader of the Irish Labour Party, 1981–82 Michael O'Leary (writer), New Zealand publisher, poet and novelist Michael O'Leary (actor), actor in the long-running American soap opera Guiding Light Michael O'Leary (businessman), CEO of low-cost Irish airline Ryanair Michael O'Leary (pioneer) (1858-1930), Australian pioneer Michael O'Leary, a character played by Humphrey Bogart in the 1939 film Dark Victory