Fred Eugene Leonard (1866-1922) was the son of Congregational minister Delavan L. Leonard (1834-1917) and Mary Louise Raymond (1838-1902). His father's occupation took the family to Wisconsin, Illinois, Missouri, Minnesota, Utah and Ohio. Fred gained a love of the outdoors and natural science while on camping trips with his father and brother (Arthur Gray Leonard 1865-1932, A.B. 1889). In 1882 he organized a chapter of the Agassiz Association, the purpose of which was to, "collect, preserve, and study natural objects." He prepared for college at the Salt Lake Academy in Utah, and graduated as the class valedictorian. After teaching in Park City, Utah and Oxford, Idaho, he came to Oberlin with his brother Arthur in 1885. There he was formally exposed to physical education, serving as director of the men's gymnasium under the direction of Dr. Delphine Hanna (1854-1941). He graduated from Oberlin College Phi Beta Kappa in 1889, and earned the M.D. degree from the College of Physicians and Surgeons at Columbia University in 1892. Upon completion of his medical course he returned to Oberlin as professor of physiology (later hygiene and physical education) and director of the men's gymnasium, a position he held for thirty years. (He also served as the registrar from 1893-1900.) Leonard was instrumental in making physical education a legitimate part of the educational experience, and succeeded in having academic credit granted for physical education on the same basis as laboratory courses. He also helped to design Warner Gymnasium which was built in 1900.

Leonard was a student of gymnasiums and gymnastic systems throughout the world. He studied abroad in 1900-01 and again in 1913, touring European gymnasiums. His travels exposed him to the developing systems of German and Swedish gymnastics, and allowed him to work with and study under many of the pioneers in the emerging field of physical training, including Baron Nils Posse (1862-1895), Luther Halsey Gulick (1865-1918), and Dudley Allen Sargent (1849-1924). Leonard also attended and taught at numerous physical education summer schools. He was a Chautauqua lecturer, and a special lecturer in the Harvard and Columbia University summer sessions. He was widely known as a contributor to educational journals, and was active in professional societies, helping to found the Ohio Physical Education Society in 1895. He was the author of Pioneers of Modern Physical Training, (1915) and Guide to the History of Physical Education, (1923). He was generally regarded by his peers as the first authority in this country on the history of physical education.

Leonard was also an active member of the Oberlin community. He was president of the Oberlin Hospital Association, a member of the Board of Education, chairman of the Oberlin Community Chest, and an advocate of temperance. In 1908 he married Bertha M. Hopkins (1879-1944, A.M. 1904), who taught women's physical education at Oberlin from 1925 to 1937, and supervised physical education for girls at Oberlin High School. The couple had three children: Robert Hopkins (b. 1911), Margaret Hopkins (b. 1914) and Barbara Hopkins Leonard (1916-2004).