Lou Costello , born Louis Francis Cristillo ( March 6 , 1906 - March 3 , 1959 ) , was an American actor and comedian best known as half of the comedy team of Abbott and Costello , with Bud Abbott . Louis Francis Costello ( March 6 , 1906 â `` March 3 , 1959 ) was an American actor and comedian best known as half of the comedy team of Abbott and Costello , with Bud Abbott .