Born in Regina, Saskatchewan, Canada, Nielsen enlisted in the Royal Canadian Air Force and worked as a discjockey before receiving a scholarship to Neighborhood Playhouse. Beginning with a television role in 1948, he quickly expanded to over 50 television appearances two years later.Nielsen appeared in his first films in 1956 and began collecting roles in dramas, westerns, and romance films. Nielsen's lead roles in the films Forbidden Planet (1956) and ThePoseidon Adventure (1972) received positive reviews as a serious actor, though he is primarily known for his comedic roles.
Although Nielsen's acting career crossed a variety ofgenres in both television and films, his deadpan delivery as a doctor in Airplane! (1980) marked a turning point in his career, one that would make him, in the words of filmcritic Roger Ebert, "theOlivier of spoofs." Nielsen enjoyed further success with The Naked Gun film series, based on a short-lived television series Police Squad! in which he starred. Hisportrayal of serious characters seemingly oblivious to (and complicit in) their absurd surroundings gave him a reputation as a comedian. In the final two decades of his career,Nielsen appeared in multiple spoof and parody films, many of which were met poorly by critics but performed well in box office and home media releases. He was recognized with avariety of awards throughout his career and was inducted into both the Canada and Hollywood Walk of Fame. Nielsen married four times and had two daughters from his second marriage.