[4] O'Neal was an artist of the Harlem Renaissance, who later studied under former Bauhaus instructors and colleagues of Ludwig Mies van der Rohe,[2] and employed early career architects including Beverly Lorraine Greene,[4] John Moutoussamy,[5] and Georgia Louise Harris Brown.
During this time, O'Neal submitted one of his paintings to the Harmon Foundation in New York City, NY., to be included in their Exhibition of work by Negro Artists (1933).
[2] In 1940-41, O'Neal worked evenings as a draftsman for Walter T. Bailey [5], Illinois' first African American licensed architect.
Beverly Lorraine Greene, the first African American woman in the United States to become licensed as an architect, briefly worked for O'Neal.
[4][8] Georgia Louise Harris Brown, the second African American woman in the country to become a licensed architect, also worked at the firm of O'Neal from 1945 to 1949.
Partly during, 1943 - 45, O'Neal served as a second class technical sergeant in the United States Army during World War II in the European theater.