William Minor Lile, who was born in Alabama in 1859, earned his LL.B. from the University of Virginia in 1882 and practiced law in Lynchburg before joining the law faculty in 1893. Lile's uncle, John Barbee Minor, had served as unofficial head of the Law School since 1845, and when Minor died in 1895, Lile assumed the role. He was not an advocate of the case method, the late-nineteenth-century innovation in legal education, but his lecture-and-textbook method of teaching was nonetheless effective, and his students loved him. After the University appointed its first president, Edwin A. Alderman, in 1904, Lile became the first dean of the Law School.

During Lile's term the Law School underwent greater changes than at any other period. Thanks to his persistent leadership, the required length of the law course was extended to two and eventually three years, and the admission requirement increased from a high school diploma to two years of college. Because Virginia did not adopt these higher standards as rapidly as other law schools, this school was not a charter member of the Association of American Law Schools, but Virginia did gain membership in 1915. The year Lile joined the faculty there were 139 law students, and by his retirement there were 257. In 1920 the first women students were admitted to the Law School, and in 1923 Elizabeth Tompkins became the first woman to earn and LL.B. Lile oversaw the construction of Minor Hall, the Law School's first building which opened in 1911, as well as Clark Hall which opened in 1932. During his deanship the faculty grew from three to five as the curriculum greatly expanded. As soon as Clark Hall opened, Lile, age 73, retired. He died in 1935.