After playing for the Milwaukee Bucks in the 2001 NBA Summer League, Moon joined the Mobile Revelers for the 2001–02 season.

After playing for the Los Angeles Lakers and the Utah Jazz in the 2002 NBA Summer League, he re-joined the Mobile Revelers for the 2002–03 season.

Moon signed a two-year deal with the Toronto Raptors on July 10, 2007, after he had impressed the coaching staff in a three-day mini-camp held by the club.

He scored 13 points for the rookies in the Rookie/Sophomore Challenge,[7] and competed in the Slam Dunk Contest,[8] finishing behind winner Dwight Howard and 2007 defending champion Gerald Green.

[9] On February 13, 2009, Moon was traded by Toronto to the Miami Heat, along with Jermaine O'Neal and conditional draft pick, for Shawn Marion and Marcus Banks.

On February 24, 2011, Moon was traded to the Los Angeles Clippers along with Mo Williams in exchange for Baron Davis and an unprotected first round pick.

[17] Moon's final NBA game was played on April 26, 2012, in a 84–104 loss to the New York Knicks where he recorded 4 points, 2 assists and 8 rebounds.

On January 8, 2014, Moon signed with the reigning back-to-back Euroleague champions, Olympiacos of the Greek League, for the rest of the 2013–14 season.

[23] On January 5, 2015, Moon signed with Guaros de Lara for the 2015 LPB season, returning to the club for a second stint.

[29] Jamario is the uncle of Xavier Moon, who plays professional basketball for Zenit Saint Petersburg of the VTB United League.