Wilbur Cleaves (1882-1978), who served as librarian from 1908-1909 while he earned his LL.B. degree, was appointed Law Registrar after he graduated in 1909. For the 1910-1911 year, he served as Secretary to the department. The next year, Professor Cleaves took a joint appointment as Law Librarian and Secretary to the department. In 1913, Professor Cleaves was also named Instructor of Law. He continued to serve as Secretary of the department and Law Librarian in addition to teaching three three-hour courses. He taught Use of Law Books to junior laws in the fall term, Damages to the middle laws in the winter term, and Domestic Relations to the middle laws in the spring term. For the 1914-1915 academic year, Professor Cleaves continued to serve in all three roles in the law department. During the 1915-1916 academic year, Professor Cleaves was on leave from the University of Texas Law Department while he earned an LL.M. from Columbia University.

While Professor Cleaves was law librarian, the library grew from 8,500 volumes to 10,000 volumes.

In 1916, Professor Cleaves returned to Texas as an adjunct professor. He taught a six-hour course, American Elementary Law, jointly with Dean John C. Townes to junior laws in the fall term. Cleaves and Townes taught Torts jointly to junior laws for six hours per week in the winter term and three additional hours in the spring term. Professor Cleaves taught Oil and Gas Mining and Irrigation to middle laws in the winter and spring terms as well as Quasi-Contracts in the fall.

In 1917, Professor Cleaves left the Law Department of the University of Texas to work as an attorney for the Humble Oil and Refining Company in Houston. He became the personal attorney of Ross S. Sterling, one of the Humble Oil Company founders, in 1925. Professor Cleaves and his son, Wilbur S. Cleaves, formed the Houston law firm of Cleaves & Cleaves in 1939. He practiced law until 1977.