He was the fifth head football coach at The Citadel, serving for five seasons, from 1916 to 1918 and from 1920 to 1921, compiling a record of 14–15–4.
[3] O'Brien also coached basketball and baseball for The Citadel for two seasons during World War I.
[4] O'Brien died of coronary thrombosis on August 23, 1955, at his home in Philadelphia.
[5][6] # denotes interim head coach Pound sign (#) denotes interim head coach.
This biographical article relating to a college football coach first appointed in the 1910s is a stub.