Colbert attended Crawford County High School in Roberta, Georgia. As a senior in 2005–06, he averaged 25 points, 13 rebounds, six assists, four steals and three blocks per game. He was named second-team all-state in Class 2A as a junior, and first-team all-state in Class 2A as a senior.
On April 12, 2006, Colbert signed a National Letter of Intent to play college basketball for Jacksonville University.
As a freshman at Jacksonville in 2006–07, Colbert earned Atlantic Sun All-Freshman team honors. In 29 games (28 starts), he averaged 11.7 points, 5.2 rebounds and 1.1 assists per game.
As a sophomore in 2007–08, Colbert had his most productive college season, scoring in double figures 24 times while going for 20 points or more three times. In 31 games (all starts), he averaged 13.1 points, 6.3 rebounds an 2.6 assists per game.
As a junior in 2008–09, Colbert became the 26th member of the school's 1,000-point club. He scored in double figures 22 times while going for 20 points or more two times. In 32 games (all starts), he averaged 11.8 points, 6.2 rebounds and 1.7 assists per game.
As a senior in 2009–10, Colbert earned second-team All-Atlantic Sun honors. In 28 games (26 starts), he averaged 12.1 points, 6.8 rebounds and 1.5 assists in 28.5 minutes per game. He finished his four-year career with 1,460 points, the thirteenth-highest point total ever for a Dolphins' player.
In August 2010, Colbert signed a one-year deal with the Plymouth Raiders of the British Basketball League. In May 2011, he signed a one-year contract extension with the Raiders. In 83 games for Plymouth over two seasons, he averaged 14.5 points, 7.0 rebounds and 3.0 assists per game.
After not receiving any contract offers for the 2012–13 season, Colbert moved to Mexico in May 2013 where he joined Leñadores de Madera of the LiMeBa Liga. It was a strange experience for Colbert, as he stated he "wouldn’t wish it on anybody" and felt unsafe in the "dangerous" country. He averaged 28 points and 10 rebounds per game over his stint with Leñadores.
In September 2013, Colbert signed with UCC Demons for the 2013–14 Irish Premier League season. He had a very successful first season with Demons, helping the team finish second on the ladder with a 16–2 win/loss record, while also helping the team win the National Cup and the Champions Trophy. In 18 regular season games, he averaged 19.8 points, 11.0 rebounds, 2.6 assists and 1.1 blocks per game.
Colbert returned to UCC Demons for the 2014–15 season, and on February 5, 2015, he earned BI Player of the Month honors for January and was named the National Cup Final MVP after leading Demons to a second consecutive National Cup title. The team went on to finish the regular season in first place with a perfect 18–0 record, garnering their seventh league title. In 18 regular season games, he averaged 22.6 points, 10.2 rebounds, 2.7 assists and 1.0 steals per game. On March 26, 2015, he was named an inaugural Premier League All-Star First Pick alongside teammates Kyle Hosford and Colin O'Reilly. Three days later, he recorded 23 points and 10 rebounds in Demons' Champions Trophy final win over Templeogue. The win created history in Irish basketball as Demons became the first side ever to remain undefeated for an entire season – a campaign that saw them win 24 games in a row.
Returning to the team for the 2015–16 season, Colbert and Demons started the new campaign with a loss to Templeogue, the team they defeated in the 2015 Champions Trophy final. On October 28, 2015, Colbert competed for Hibernia, Basketball Ireland's newly established European competitions' team, in the inaugural round of the 2015–16 FIBA Europe Cup. Colbert finished the game with eight points as Hibernia were defeated heavily by Danish team Bakken Bears, losing 96–60. In Hibernia's fourth game of the tournament on November 18 also against Bakken, Colbert recorded a double-double with 20 points and 10 rebounds. Over six games for Hibernia, he averaged 13.3 points, 5.3 rebounds, 1.7 assists and 1.2 steals per game.
On January 8, 2016, Colbert scored 21 points in Demons' National Cup semi-final loss to Swords Thunder. Demons went on to win their second consecutive league title after finishing first on the ladder with a 16–2 record. Colbert again appeared in all 18 regular season games for Demons, averaging career highs of 23.4 points and 12.3 rebounds, as well as 2.8 assists and 1.1 blocks in 34.3 minutes per game. On March 19, he recorded 35 points and 17 rebounds in Demons' 75–71 Champions Trophy semi-final win over UCD Marian. The next day, he recorded 27 points and 16 rebounds in Demons' 82–77 Champions Trophy Final win over Killester, as he claimed game MVP honors and his third Champions Trophy title in three seasons. In June 2016, he was named Men's Premier League Player of the Year. He was also named a Premier League All-Star First Pick for the second year in a row.
After sitting out the 2016–17 season, Colbert returned to UCC Demons for the 2017–18 season. He was unable to play in the season opener however due to his work permit still being processed.
Colbert is the youngest of six children to mother Irene and father Lehmon Sr., who died when Colbert was 18. His daughter, Kyla, was born in 2011.