J. Paul Leonard was a native of Lockwood, Missouri. He graduated with a BA from Drury College, Missouri, then went on to Columbia University where he earned his MA in 1927; two years later he was awarded his PhD. In the same year he married Miss Johnnie Lueille Ferguson, and later had two children. In 1955, at the bicentennial celebration, Leonard was awarded the Doctor of Humane Letters degree, in recognition of his contribution to the service of education in the US.

He was inaugurated president of AUB at the Commencement ceremony on July 1, 1957. On December 17, 1957, Drs. Farid S. Haddad, president of AUB Alumni Association awarded Leonard the Daniel Bliss Gold Medal; on the 21st he was awarded the Lebanese Order of the Cedars medal. He retired on December 31, 1960.

President Leonard devoted his lifetime to the service of education, and received recognition with a number of honors from the US. In addition to his tireless devotion to his field, he also found time to participate in various
committees, clubs and community projects.