The Extension Division (1921-1957) was the unit at Brigham Young University responsible for coordinating distance education and extension work. The Extension Division was established in 1921 in a reorganization of the earlier Extension Department. It was charged with providing educational services to those outside the university campus, such as off-campus programs, lectures, classroom offerings, and correspondence courses. Directors of the division included Lowry Nelson (1921-1936), Harrison R. Merrill (1936-1939), Carlton Culmsee (1939-1944), Gerrit de Jong (Acting Director, 1944-1946), Thomas L. Broadbent (Acting Director, 1946-1947), and Harold Glen Clark (1947-1957). In 1957 the unit was renamed as Adult Education and Extension Services.

Adult Education and Extension Services (1957-1964) was the unit at Brigham Young University responsible for coordinating distance education and extension work. The division of Adult Education and Extension Services was established in 1957 in a reorganization of the earlier Extension Division. The unit was charged with providing educational services to groups outside the normal day enrollment of the university. Harold Glen Clark served as the dean of the division from its establishment until its reorganization in 1964 as the Division of Continuing Education.

Harold Glen Clark (1902-1984) served as the Dean of Continuing Education at Brigham Young University. Harold Glen Clark was born in 1902 in the Salt River Valley, Arizona. After serving a mission for the LDS church, Clark attended Columbia University and later Brigham Young University. In 1929 he returned to Mesa and married Virginia Driggs. After receiving a Master's Degree in Educational Administration from the University of Southern California, Clark went on to serve as the secretary of congressman John R. Murdock in 1936 and received a doctorate degree at George Washington University. In 1944, Clark became the personnel trainer in the Triple A Program of the US Dept. of Agriculture. Returning to Utah in 1946, Clark took a position as Professor of Education at Brigham Young University. In 1950 Clark's wife Virginia died from cancer, and Clark was remarried later that year to Mary Deane Peterson. Clark's later positions at BYU included the Director of Extension Services in 1947, the Dean of Adult Education and Extension Services, and the Dean of the Division of Continuing Education. Clark served in various church positions in his life, inluding high councilman, bishop, and president of the Provo Temple from 1971-1977. Harold and Mary Dean Clark also served a mission in Sri Lanka from 1979-1981.