He was also named the 1999 Illinois Mr. Basketball after averaging 21.7 points, 10.1 rebounds, 3.2 blocks, 2.0 steals and 1.8 assists per game as a senior.

[4] Cook played 132 games in four years for the University of Illinois, most of them under coach Bill Self, and led the Illini in rebounding in each season.

Cook was a versatile scorer from both inside and outside the paint, utilizing his height to score in the post and hitting three-point shots when left open.

Cook helped lead the Illini to a number one seed in the 2001 NCAA Tournament, and the Illini cruised to the Elite 8, where they were upset in a hard-fought and controversial game by Cook's future teammate Luke Walton and the Arizona Wildcats.

As a senior in the 2002–03 season, Cook led the Fighting Illini in scoring with 20.0 points per game, and received the Chicago Tribune Silver Basketball as the Most Outstanding Player of the Big Ten Conference.

Additionally, he would lead the Illini to the Big Ten men's basketball tournament championship and be named Most Outstanding Player.

As his professional career evolved, however, Cook once again became a player who could play beyond the perimeter, after O'Neal moved on to the Miami Heat and Rudy Tomjanovich took over for Phil Jackson as Lakers' head coach.

On November 20, 2007, Cook was traded, along with Maurice Evans, to the Orlando Magic in exchange for Trevor Ariza.

[9] On March 15, 2012, Cook was traded, along with a 2015 second-round pick, to the Washington Wizards in exchange for Nick Young.