As a member of the Boston College basketball team, Williams began his career as a standout in the paint.

The police report stated he was belligerent while being arrested, writing obscenities instead of his name on the fingerprint card and trespass warning.

[3][4] On March 16, 2009, Williams was arrested and charged with disorderly conduct and criminal mischief after an altercation with the clerk at a cell phone store at Park Meadows Mall in Lone Tree, Colorado, that ended with Williams smashing the store's computer monitor.

[10] After being released by the Nets, Williams went to play for the Fujian SBS XunXin of the Chinese Basketball Association (CBA).

[11] Some of his notable performances in the CBA include 30 points against Qingdao DS on March 12, 2010, and 13 blocks against Jilin on February 26, 2010.

[12] Williams landed in Puerto Rico to end his 2009–10 season, joining the Mets de Guaynabo, where he averaged 10.0 pts and 16.5 rebounds in 2 games.

Williams earned a spot in the 2011 All-NBA Development League Third Team and also ranked second in voting for the Defensive Player of the Year category.

[19] Williams played his first game for the Mavericks in their 115–93 loss to the Denver Nuggets on December 26, 2011, providing some much needed spark off the bench in the 3rd quarter.

Williams went 4–4 from the field, which included two high flying alley-oops, and 4–4 from the free throw line and picked up 3 rebounds, a steal and a block in his 11 minutes of game time.

[24] On April 20, 2012, Williams was signed by the Boston Celtics, returning to the city where he played college basketball.

[29] On August 29, 2013, Williams' rights were acquired by the Delaware 87ers in the 2013 NBA Development League Expansion Draft.