Dr. Duncan, like E. O. Lyte, centered his career at Millersville, enjoying a 46-year association with the college. He came to Millersville in 1935, completed his two-year course in 1936, and taught in Strasburg while meeting the requirements for a bachelor's degree at Millersville (granted in 1940). After several years teaching, serving in World War II, and earning a master's degree at Penn State University, he returned to Millersville in 1947 as a social studies teaches in the laboratory junior high school. He subsequently left the classroom except for occasional part-time service to devote his time to administrative duties. He held such positions as the director of admissions, registrar, acting dean of instruction, and dean of student affairs prior to his appointment as president. He oversaw the continuing building boom of the 1960's and early 1970's, the decline of state appropriations in the 1970's, the change of emphasis from teacher training to liberal arts, and burgeoning enrollments.