After leaving Oklahoma, Mitchell joined the military and then attended law school. He moved to Atlanta, Georgia, where in the 1960s he joined the Nation of Islam (NOI) and took the name Hulon X. After leaving the NOI in the late '60s, he became a faith healing Christian preacher and named himself Father Mitchell, fashioning himself after Father Divine and Samuel "Father Jehovia" Morris, two African-American ministers and self-proclaimed divine connections to God who were active during the early 20th century. Mitchell arrived in Miami, Florida in 1978, where he gathered members of the city's Black Hebrew Israelite congregations and founded the Nation of Yahweh.