Timothy J. Sullivan first came William & Mary as a freshman in 1962. He graduated in 1966 with a bachelors degree in government, a Phi Beta Kappa key, and membership in Omicron Delta Kappa. After receiving a law degree from Harvard University in 1969, Sullivan went on to serve in the Army Signal Corps in Vietnam, where he received the Army Commendation Medal, First Oak Leaf Cluster and Bronze Star.

Sullivan came back to William & Mary in 1972 as an assistant professor at the Marshall-Wythe School of Law where he specialized in teaching contract law. He became an associate law professor in 1974, then full professor and associate dean in 1977. In 1981 and 1982, he was visiting law professor at the University of Virginia School of Law. He served for nearly three years as executive assistant for policy for then-Governor Charles S. Robb. Sullivan returned to Marshall-Wythe in 1984, as the John Stewart Bryan Professor of Jurisprudence. He became dean of the law school in July 1985. He is a member of the Virginia State Bar and the Ohio State Bar and a Fellow of the Virginia Bar Foundation and the American Bar Foundation, and he served as Chair of Governing Board, Council of Presidentts.

Sullivan was elected president of William & Mary on April 9, 1992 by the Board of Visitors and was sworn in as president on June 1, eight months before the college began its 300th anniversary celebration. Sullivan served as president until June 30, 2005.