He studied at the Lorne Greene Academy of Radio Arts in Toronto before going to the United States.
Initially a serious dramatic actor, with roles in the 1950s science fiction classic Forbidden Planet, his career shifted later as Nielsen starred in a succession of broad comedies.
His comedies include The Naked Gun series, Flying High (also known as Airplane in its American release), and a large number of other spoofs and comedies. He specialised in spoofing popular movie styles and conventions, and his movies have sent up Disaster movies, Hospital dramas, Vampire and horror movies, action blockbusters etc.
His brother, Erik Nielsen, is a former Deputy Prime Minister of Canada.
Leslie Nielsen has a Star on the Hollywood Walk of Fame at 6541 Hollywood Blvd, and has been inducted into Canada's Walk of Fame.