Jennings was born on May 16, 1898, in Washington, D.C., but was just few weeks old the family moved to Charleston, where his father was the postmaster.
[2] Jennings trained for service in World War I at the Porter Military Academy, but was discharged because he was born with a cleft palate.
[2] At first he attended College of Charleston, but then moved to Columbia University and Carnegie Technical Institute, where he studied art, stagecraft and design.
[1] A gay man, many of his works include homoerotic themes; most of them are housed at the Gibbes Museum of Art.
[1][2] Harlan Greene in the novel Why We Never Danced the Charleston based the character of Ned Grimke on Jennings.