Robert Morton Hughes was an alumnus of William & Mary (1870-1873) and also attended the University of Virginia Law School. He was the son of Robert William and Eliza M. (Johnston) Hughes. He practiced law in Norfolk, Virginia. Hughes was the president of the Virginia Bar Association; biographer of Joseph Eggleston Johnston.
Hughes entered William & Mary in 1870 at the age of 15 and graduated with an A. B. degree in 1873. His association with William & Mary continued for the rest of his life. Hughes was president of the Alumni Association for 1892-1893, and served on the Board of Visitors from 1893 to 1918 and was rector from 1905 to 1918. In 1920 the College awarded him an honorary doctor of laws degree. In 1933, Hughes was the commencement speaker. Washington & Lee University awarded him an honorary doctorate of laws degree in 1926. Hughes was a member of the Virginia State Board of Education from 1930-1935. For his part in establishing what became Old Dominion University, in 1959, the Robert M. Hughes Memorial Library was named for him.