American comedian Lou Costello wasn't the most scholarly of lads growing up in Paterson, New Jersey, although he excelled in baseball and basketball. He won an athletic scholarship to Cornwall-on-Hudson Military School, but left before graduation to try a performing career. Reasoning that there'd be a lot of work for a top athlete in Hollywood, Lou travelled westward, but was only able to secure stunt-man work, specializing in the sort of spectacular falls that he'd still be staging during his later starring career. Tired of working anonymously in Hollywood, Costello decided to give stage work a try, and by the mid '30s he'd achieved minor prominence as a burlesque comedian. What he needed was the right straight man, and that man was Bud Abbott, with whom Lou teamed in 1936. Abbott was satisfied in burlesque, but Costello had bigger ambitions; it was he who actively promoted the team into radio and Broadway. In 1940, Lou finally realized his life's ambition to be a movie star when he and Abbott were signed by Universal Pictures. The team's second feature, Buck Privates, launched an amazingly durable film career; for the next ten years, Abbott and Costello were Hollywood's biggest moneymaking team. Though no pushover in real life, Lou became world famous for his portrayal of the hapless, trodden-upon patsy of the conniving, bullying Abbott; his plaintive "I'm a ba-a-ad boy" became a national catchphrase. A serious 1942 bout with rheumatic fever kept Lou out of radio and films for a full year. On the day of his professional return in 1943, an appalling tragedy struck Costello; his infant son drowned in the family's backyard swimming pool. Waving off mourners, Lou performed his comeback radio show that evening on schedule, as funny as ever, and broke down the minute the show signed off, while a visibly shaken Bud Abbott explained the situation to the studio audience. Lou was never quite the same after that, though his career flourished, surviving the occasional falling out with Bud Abbott and unprofitable attempts to change his screen image in such films as Little Giant and The Time of Their Lives (1946). Seldom making a professional misstep -- he moved from films to TV and back again with enormous success. Costello broke up permanently with Bud Abbott in 1956. His solo dates in nightclubs and television were satisfactory, and a starring appearance as a single in The Thirty Foot Bride of Candy Rock (1959) wasn't the disaster it might have been, but Lou Costello was basically unhappy going it alone. Still, he was thriving in show business and seemingly had a rosy future ahead of him in early 1959; sadly, in March of that year Lou Costello lost his lifelong battle with his rheumatic heart and died three days before his 53rd birthday.

Lou's brother Pat Costello (Anthony Sebastian Cristillo) often doubled and did stunt work for his brother in the movies.