After turning pro, Campbell got his start on mini-tours such as the NGA Hooters Tour and the Buy.com Tour (now called the Nationwide Tour). Campbell secured 13 victories on the NGA Hooters Tour before moving to the Buy.com Tour in 2001. Following three wins in 2001 that resulted in Campbell being named the Buy.com Player of the Year and the tour's leading money winner, he earned a spot on the PGA Tour.
Campbell's first win on the PGA Tour came in 2003 at the Tour Championship. That year would prove to be a breakout season for Campbell as he finished seventh on the PGA Tour money list with nearly $4 million in earnings. Campbell's next win came at the 2004 Bay Hill Invitational and he also prevailed at the 2006 Bob Hope Chrysler Classic and 2007 Viking Classic.
Although he's yet to win a major tournament (as of August 2009), Campbell has come agonizingly close on a handful of occasions. He finished second twice (2003 PGA Championship and 2009 Masters) and tied for third at the Masters in 2006. At the 2003 PGA Championship, Campbell lost in a playoff to unlikely winner Shaun Micheel. He was unable to prevail in a playoff for a second time at the 2009 Masters, surrendering to eventual winner Angel Cabrera.
Campbell played in Ryder Cup competitions in 2004, 2006 and 2008 and was part of an American team that snapped a string of three straight losses to the Europeans in 2008. He's compiled a record of 3-4-2 during Ryder Cup play, including a 2-1-1 mark during singles competition.
Along with his wife, Amy, Campbell currently resides in the Fort Worth, Texas, area. Campbell is a supporter of several charitable causes and has been featured on PGA Tour commercials highlighting players giving back in the community. For his career, Campbell has accumulated over $17 million in total earnings.