Educated at Horner Military Academy in Oxford and at Davidson College, he went on to attend classes at the Art Students League in New York.
[1] Upon winning a scholarship for study in Europe, he travelled there, learning an academic style of portrait painting.
He returned to the United States, working as a professional portraitist in New York City and North Carolina.
Long went on to serve in World War I, and abandoned his artistic career afterwards, being ordained as a Presbyterian minister in 1922, becoming an evangelist in the southern U.S.[2] In his seventies, Reverend Long began painting again, in a far more surrealistic fashion that widely differed from the style of his previous portraiture.
[3] The Presbyterian Historical Society in Philadelphia, Pennsylvania, has McKendree Robbins Long's Papers, including written and printed materials; original drawings, sketches, and illustrations; a folder of photographs; and seven sermons recorded on Duodisc electric transcription discs.