Banks was selected as the thirteenth pick in the first round of the 2003 NBA draft by the Memphis Grizzlies; however, he was then traded to the Boston Celtics along with Kendrick Perkins for Troy Bell and Dahntay Jones. The Celtics agreed to trade him to the Los Angeles Lakers in 2004 for Gary Payton, but returned to Boston after the trade was amended following Payton's refusal to take a physical. Payton would later be acquired by the Celtics in a trade involving different players.
In 2007, the Suns spent training camp working Banks into a shooting-guard role when they were not seeking a trade, a tough proposition with Banks in the second year of a five-year, $21.3 million contract.
On February 6, 2008, Banks, along with All-Star forward Shawn Marion, was traded to the Miami Heat for Shaquille O'Neal.[5] On February 13, 2009, Banks and Marion were traded to the Toronto Raptors for Jermaine O'Neal and Jamario Moon.[6] Banks' final game in the NBA was during his time with the Raptors on November 16, 2010, in a 94–109 loss to the Washington Wizards. In his final game, Banks recorded 2 points and 2 assists.