In November 1903 he was appointed a minister in the African Methodist Episcopal Zion Church in Salisbury. In 1905 he married Rose Douglas, a native of Virginia, with whom he had four children. In the same year he began to teach at Livingstone College. In 1912 he earned his doctorate in theology, and in 1914 followed a doctorate in osteopathy. In the same year he transferred employment to a small municipality to North Carolina. Between 1915 and 1917 Aggrey took up further studies at what is now known as Columbia University, where he studied sociology, psychology and the Japanese language.