The older brother of Georgetown forward James Colliflower, George Colliflower graduated from Georgetown Prep in 1898 and Georgetown College in 1902. George joined his brother for three years on the varsity while both were enrolled in law school. Colliflower was a reserve forward for three seasons through 2010, then played a fourth year while his brother served as head coach.

Following school, Colliflower coached at Gonzaga College High School for one season and was the head coach at George Washington from 1915-1917, with a cumulative record of 9-18. Colliflower entered the family coal business but often officiated high school and college games.

His death in 1980 marked the passing of the last of the founding era athletes for the sport at Georgetown.