He played high school basketball in his native city of Houston, and he spent two years at Southwest Missouri State in the MVC before transferring to Southern Miss, where he played his two remaining years of college basketball eligibility.
After going undrafted in the 2004 NBA draft, he started his professional career in the Continental Basketball Association with the Michigan Mayhem, leading the league in rebounding.
Gaines was born in Houston, Texas and attended Klein Forest High School, where he was a member of the varsity basketball team.
[1] As a senior he stood at 6-foot-7 and weighed 200 pounds: he averaged 20.6 points, 8.7 rebounds[1] and 3 blocks[2] per game, contributing to the team's 20–12 record.
[1] Gaines signed to play for Southwest Missouri State, the first recruit brought to the program by newly appointed coach Barry Hinson.
[1] He could play multiple positions, and was projected to be mainly used as a forward,[2] though he could also cover the shooting guard spot.
[3][4] He ended the season with averages of 3 points, 2.1 rebounds, 0.1 assists and 0.7 blocks, having played all of his 32 games coming off the bench.
He was selected with the 4th pick in the 8th round of the 2004 National Basketball Development League draft by the Huntsville Flight (46th overall), but instead of signing with the team Gaines decided to join the Michigan Mayhem, which played in the Continental Basketball Association: in the 2004–05 season he played 44 games (30 starts) and averaged 18.3 points, 11.4 rebounds, 0.7 assists, 1.2 steals and 0.5 blocks per game.
He stayed with the team for the 2009–10 season and posted averages of 30.4 points and 10.7 rebounds in 39.4 minutes per game over 43 appearances.
[15] He ranked second in scoring with 30.4 points per game behind Andre Emmett for the 2009–10 season and was a first-team All-CBA selection.
On January 2, 2013, in a game against the Zhejiang Golden Bulls, Gaines scored 60 points and posted 29 rebounds, both career-highs.
[24] He repeated this feat in the following season, during which he averaged 16.4 rebounds per game playing for the Zhejiang Golden Bulls.
[26] In 2017 Gaines signed for the Shaanxi Wolves in the National Basketball League, the second level of Chinese basketball, and won the league title, scoring 31 points and grabbing 14 rebounds in the decisive 5th game of the championship series against Anhui.
[27] In the following season he signed for the Anhui Dragons, averaging 33.8 points per game (6th best in the league), 17.5 rebounds (3rd best) and 2.4 steals (4th best).