He was born in Chicago to Guyanese parents. He graduated from Bolingbrook High School in Bolingbrook, Illinois in 2007. Doris was a two-time junior college national champion at the College of DuPage before transferring to the University of Iowa. Prior to competing in the 2016 Olympics, Troy was a physical education teacher at a Noble Network Charter school, Chicago Bulls College Prep, in Chicago, Illinois. Before choosing to compete for Guyana, he placed eighth at the 2012 U.S. Olympic Trials in the triple jump.