He played in the National Basketball Association (NBA) for the Philadelphia 76ers, Dallas Mavericks, Utah Jazz, Phoenix Suns, Charlotte Bobcats, and Golden State Warriors.

Bell began his professional career with the Yakima Sun Kings of the Continental Basketball Association (CBA).

The little-used Bell starred in Game 7 of the 2001 Eastern Conference Finals, scoring 10 points (all in the 2nd quarter) and rallying the Sixers from an early deficit against the Bucks as the 76ers won easily.

On October 1, 2002, Bell signed as a free agent with the Dallas Mavericks, and he averaged 3.1 points in 15.6 minutes per game.

One of the most notable incidents of Bell's career occurred in the 2006 NBA Playoffs on May 2, 2006, in Game 5 of a first round series against the Los Angeles Lakers.

Bell clotheslined Lakers shooting guard Kobe Bryant on a hard foul, resulting in an ejection (with 7:33 left to play in the game).

[7] Bell finished the 2006–07 season with 205 total three-point shots made, tying the Washington Wizards' Gilbert Arenas for the league lead.

[8][9] On December 10, 2008, Bell was traded to the Charlotte Bobcats along with Boris Diaw and Sean Singletary in exchange for Jason Richardson, Jared Dudley and a 2010 second-round draft pick in a move by the Suns to retool their roster.

[10] This came after a disappointing start to the season for Bell during which he posted just 9.6 points per game and saw a diminished role under new coach Terry Porter.

On November 16, 2009, Bell was traded to the Golden State Warriors along with Vladimir Radmanović in exchange for Stephen Jackson and Acie Law.

[13] Bell's trade to the Warriors notably cleared the way for Steph Curry to be the long-term point guard for Golden State, as he had previously been benched for Acie Law.

On May 2, 2007, Cindy gave birth to their first child, Dia, by c-section six hours before tip-off of Game 5 against the Los Angeles Lakers in the 1st round of the 2007 NBA Playoffs.

[23] On June 17, 2024, Raja's son, Dia, announced his commitment to play football for the University of Texas at Austin.

[24] In July 2020, Bell created a Twitter account with the username RajaBell19,[25] a nod to the number he wore most often as an NBA player.