Jamison spent the first five years of his NBA career with the Warriors, and was often the only bright spot on a low-performing team. He averaged a career-high 24.9 points per game in 2000-01, his third season in the league. In 2003, he was traded to the Dallas Mavericks in an eight-player deal, and experienced his first winning season in 2003-04 as the Mavericks finished 52-30 and made the playoffs. Jamison was also named as the NBA's Sixth Man of the Year for his efforts. Unfortunately for the Mavericks, they suffered an embarrassing setback in the first round, falling in five games to the Sacramento Kings.

At season's end Jamison was traded again, this time to the Wizards, in exchange for fellow former Tar Heel Jerry Stackhouse, Christian Laettner, and a first round draft pick (which turned out to be University of Wisconsin point guard, Devin Harris).

In the 2004-2005 season with the Wizards, he was named to the NBA All-Star team for the first time in his career and the Wizards enjoyed a stellar 45-37 win-loss season, their finest effort in 26 years. They also made the playoffs for the first time since 1997 and advanced to the second round for the first time since 1982.

Jamison played high school basketball at Providence High in Charlotte, North Carolina. Jamison has also launched a campaign which he calls "A Better Tomorrow" which he hopes to use to provide the underprivileged which a chance at a better future. He says of the project: "As a professional athlete, I have an obligation to help those less fortunate. I really enjoy being in a position to aid my community - both in the Bay Area and back home in Charlotte - and put a smile on somebody's face. That is what it is all about. I think it is especially important to give back during the holidays, when people tend to feel a little down if things are not going too well."