He played college basketball for the Duke Blue Devils where he started at power forward for the national champion 2010 team.

He led the school to two Prep A Division New Jersey State titles with a 56–3 record in his final two seasons while averaging 14.5 points and 6.5 rebounds per game his senior year.

In 2005, Thomas played at the USA Basketball Youth Development Festival where he helped the Blue Team win the silver medal with a 3–1 record.

[2] After committing to Duke University on April 5, 2006, Thomas played for the Under 18 national team at the FIBA Americas Under-18 Championship where he helped USA win the gold medal.

He posted a .505 field goal percentage and recorded at least five rebounds 12 times, including eight of Duke's 16 ACC games.

[5] In his senior year, Thomas and All-American point guard Jon Scheyer were co-captains of Duke's team.

However, Thomas suffered a severe bone bruise to his right knee early in the second half, forcing him to miss the next game against Maryland.

[7] In the 2010 NCAA championship game, Duke faced Butler and star swingman Gordon Hayward.

[8] Thomas was named to the 2009–10 ACC All-Defensive Team for 2010 and finished his college basketball career ranked 10th on Duke's all-time list in offensive rebounds (255).

[10] He made the Hornets' roster for the start of the lockout-shortened 2011–12 NBA season, but he was later waived by the team on December 31.

[22] Thunder head coach Scott Brooks said of Thomas, "Lance is a hard worker.

[32] Prior to the start of the 2017–18 season, Thomas was named co-captain of the Knicks alongside Courtney Lee.

[37] In 2011, Thomas was a member of the US national team that won a bronze medal at the Pan American Games.