Mary Elizabeth Branch, college president, was born near Farmville, Virginia, on May 20, 1881, the daughter of Tazewell and Harriett Branch. Although few African Americans received a public education in the late nineteenth century, the Branch children attended Farmville's elementary school. Their parents, born slaves but now members of a developing Black middle class, also taught their children at home. After completing high school studies in the normal school at Virginia State College, Petersburg, Mary Branch became an English teacher in the elementary school at Blackstone, Virginia. Later she joined the faculty of her alma mater, where she remained for twenty years. She was a challenging and popular instructor and also served as the college's housing director. During summers she attended the University of Pennsylvania, Columbia University, and the University of Chicago. The last granted her a bachelor's degree in 1922 and a master's degree in English in 1925. She also began studies there towards a doctorate in education. Towards the end of her career she received honorary degrees from Virginia State College and Howard University.
Branch began teaching social studies at Sumner Junior College in Kansas City, Kansas, in 1927. In 1928 she became dean of women at Vashon High School in St. Louis, which was then the largest school for Black girls in the country. In 1930 the American Missionary Association appointed her president of Tillotson College in Austin, Texas. A troubled institution, Tillotson had been forced by declining enrollments and poor administration to reorganize as a junior college for women in 1929. As president, Branch sought to make Tillotson a successful and respected four-year college once more. Under her direction the college's facilities were improved. The library expanded. Old buildings underwent renovation, and new buildings, including a men's dormitory and a gymnasium, were constructed. In order to attract new students and strengthen the educational program, Branch abolished the high school program and increased the college budget. She also doubled the size of the faculty and raised education requirements for instructors. She recruited students throughout the Southwest and offered scholarships to the most needy. In an effort to give Tillotson a more contemporary atmosphere, Branch abolished mandatory chapel, permitted the organization of fraternities and sororities, and encouraged the formation of academic and athletic clubs. Throughout her tenure she also worked to improve the college's relationship with the community by participating in civic affairs and establishing contacts with faculty at the University of Texas and Samuel Huston College, as well as with public school teachers and administrators. She also worked towards a merger with Samuel Huston College, although the two institutions did not join until after her tenure.
During the Branch administration enrollment steadily grew. Moreover, in 1935, Tillotson reorganized as a coeducational, four-year institution. In 1936 the college was admitted to membership in the American Association of Colleges, and in 1943 it received an "A" rating from the Southern Association of Colleges and Secondary Schools. While in Austin, Mary Branch became active in the civil-rights movement. She became president of the Austin chapter of the National Association for the Advancement of Colored People in 1943. She also served on the State Interracial Commission of Texas. During the Great Depression she devoted much time to the National Youth Administration. In 1935 Lyndon B. Johnson appointed her to the NYA Negro Advisory Board for Texas. In 1944 Branch helped to establish the United Negro College Fund. She died in Baltimore, Maryland, on July 6, 1944, at the height of her career.