After graduating from college, he went on to play professional basketball for 13 years, mainly in Europe: he led the German Bundesliga in scoring in the 1997–98 season and was named an All-Star in Greece, Germany, and France.

[8] In his career at Conley he scored 1,612 points, with a 56% field goal percentage and shooting 92% on free throws, and he also averaged at least 6 assists per game in each season he played.

[3] Gatlin was heavily recruited during his high school career, and received offers from 210 colleges;[4] he committed to Maryland in October 1982, choosing to major in radio and television.

[3] He chose to wear jersey number 3[9] and in his freshman year he started 9 games out of the 32 he played, averaging 6.2 points, 1.6 rebounds and 4.6 assists in 23.7 minutes per game: he recorded a season-high 19 points vs. Georgia Tech and 10 assists in the ACC championship final versus Duke, during which Maryland won the 1984 ACC men's basketball tournament.

[6] In his sophomore season Gatlin was named a starter by coach Lefty Driesell, and he improved in all statistical categories: in 30.6 minutes per game he averaged 8.3 points, 1.9 rebounds and 6.0 assists.

Gatlin returned his junior year with a more important role within the team, since coach Driesell believed he was one of the key players for Maryland.

[10] After the death of Len Bias, which happened after the end of the 1985–86 season, the Maryland program was in turmoil and several players were suspended for skipping class and having poor grades: Gatlin was one of them.

[11] He was suspended for academic issues and missed the entire 1986–87 season, which was supposed to be his senior year in college basketball.

[19] In 1990 he joined the New Haven Skyhawks of the United States Basketball League, and he was free throw percentage leader with .899 in 1991.

[24] During his time at Wesleyan he won two back-to-back NCISAA championships in 2013 and 2014; in July 2018 Tubby Smith chose him for the assistant coach position at High Point University.