Mary Leonard is the co-owner of U.S. Athletic Training Center. She is Director of Marketing and Patient Care at Gary Guerriero P.T., P.C. Before opening U.S.A.T.C., Mary was a professional theater dancer and performer appearing on multiple television shows and performing on Broadway. She has choreographed in many mediums ranging from television to stage. She was named one of the "55 Best Trainers in America" by Vogue magazine. She is a published exercise author and has been featured in national publications, including Vogue, New York Times, Daily News, Glamour, Men's Journal, W, American Health, Bazaar, New York Magazine, Ski, Dancer Magazine, Self, The Red Bulletin, Shape, Fitness Magazine and in Good Housekeeping presented by L'Oréal 50 Inspiring Women Over 50.

She taught dance for the American Dance Machine and Marymount Manhattan College. Mary was also the head of the weight training program and taught fitness aerobics and swimming at Barnard College. She holds a Master's Degree from Columbia University. Mary still trains select clients, usually in the performing arts.