Frank Croker was the second son of Richard Croker, a Tammany leader in New York City. Born in New York City, he attended Brown University with his elder brother, Richard, Jr. After leaving college, he started a business career, becoming a Director of the Atlantic Coast Realty Company, a Director of the Casualty Company of America, and the Secretary and Director of the Roebling Construction Company.
While at college, Croker's love of athletics made him one of the best-known members of the class of 1901. He played on the class football team and on the varsity baseball team. In 1903 he took up motor racing.