Greg Reid's father served a six-year sentence for drug trafficking, according to the St. Petersburg Times and Orlando Sentinel. Reid's father received consideration for a release to see his son play against Brigham Young on September 17, 2010 for the first time. "It's going to mean the world to me," Reid said. Reid's father was released in December 2010, just prior to the 2010 Chick-fil-A Bowl in which he was named defensive MVP.
After a senior season in which he rushed for over 1200 yards, scored 18 touchdowns and had nine interceptions, Reid was named the fourth best cornerback in the nation, and the top overall prospect in Georgia. He also earned All-American honors from Parade and SuperPrep, the Atlanta Journal-Constitution named him "Georgia Player of the Year", and he was named the class five-A "Georgia Player of the Decade".
Reid was heavily recruited out of high school, earning five star ratings from both Rivals and Scouts, and received scholarship offers from Alabama, Auburn, Florida (he initially chose Florida over FSU during the recruiting process) and Georgia, among others.
Due to a lack of depth at the cornerback position, Reid played all thirteen games of the 2009 season, intercepting two passes, and leading the NCAA in punt return average".
On August 1, 2012, Reid was dismissed from the Florida State Seminoles on account of violating team rules. He later transferred to Valdosta State University, which is located in the same city as his high school.
Reid signed with the St. Louis Rams on March 24, 2014. The news came two days after the Rams held a private workout for him. He was waived during final cuts on August 30, 2014.
He was assigned to the New Orleans VooDoo on December 23, 2014.
Reid participated in the first inaugural NFL Veteran Combine on March 22, 2015.
On April 29, 2015, Reid was assigned to the Jacksonville Sharks. Reid's great play lead him to being named to the First Team All-Arena squad as well as the AFL Rookie of the Year.
On May 30, 2017, Reid was assigned to the Tampa Bay Storm. He was placed on league suspension on June 8, 2017.
Reid signed with the Monterrey Steel for their postseason run.