Croll was born in 1920 in Bryn Mawr, Pennsylvania. After finishing high school, he attended the
University of Pennsylvania with the intention of becoming a
veterinarian but left to pursue his passion for racing Thoroughbreds. In 1940 he obtained his trainers' license but his racing career was interrupted by service with the
United States Army in the
Pacific Theater of Operations during
World War II. Upon the 1946 opening of the new
Monmouth Park Racetrack in
Oceanport, New Jersey, Croll relocated there and became a permanent part of that facility's annual summer campaign. In 1998, he received Monmouth Park's "Raines Distinguished Achievement Award" given in memory of trainer
Virgil W. Raines to an owner or trainer who has shown a dedication to the sport of Thoroughbred racing through exemplary conduct demonstrating professionalism and integrity.
He earned his first
graded stakes race win with War Phar in 1951. Although Croll has had a number of good horses, there are several that stand out:
Jimmy Croll conditioned horses for Rachel Carpenter for 37 years. At the time of her death in August 1993, she owned Croll's most famous horse, the then unraced Holy Bull. Just a few hours before the two-year-old colt made his racing debut, Croll was notified by telephone that in her will, Rachel Carpenter had bequeathed him the seven horses under his care which included Holy Bull.
^Handleman, Bill.
"Track's history a story of a Shore playground", Asbury Park Press, September 27, 2007. Accessed December 14, 2007. "Holy Bull, Horse of the Year as a 3-year-old in 1994, was owned and trained by Jimmy Croll, who still lives in Monmouth Beach."