[2] After a brief career at Racine Park High School,[3] he enrolled at Maine Central Institute where he was successful enough to receive a scholarship to attend the University of Connecticut to play for the Connecticut Huskies men's basketball team for coach Jim Calhoun for two years.

[4] The summer after his freshman season, he started for the US team that took home gold in the 2001 FIBA World Championship for Young Men.

[5] Butler improved as a sophomore, averaging 20.3 points and 7.5 rebounds per game, leading the Huskies to regular-season and tournament Big East titles.

In the first round, the Heat and the New Orleans Hornets battled in a grueling 7-game series in which the home team won every game.

After the season, Miami traded Butler, Odom and Brian Grant to the Los Angeles Lakers for superstar center Shaquille O'Neal.

The Lakers traded Butler and Chucky Atkins to the Washington Wizards for Kwame Brown and Laron Profit.

On January 17, 2007, Butler made his first game-winning basket, a dunk off a pass from DeShawn Stevenson with 2.2 seconds remaining against the Knicks to give the Wizards a 99–98 win.

[12] He broke his hand late in the season attempting to block a shot and sat out the playoffs, along with the injured Gilbert Arenas, and the Wizards were swept in their opening-round rematch with the Cavaliers.

In the 2007-08 season, Butler, who was sidelined with a hip injury, was nonetheless selected as a reserve for the East in the 2008 NBA All-Star Game in New Orleans, Louisiana.

[13] On February 13, 2010, Butler was traded to the Dallas Mavericks along with Brendan Haywood and Deshawn Stevenson for Josh Howard, Drew Gooden, James Singleton, and Quinton Ross.

[14] The Mavericks qualified for the 2010 NBA Playoffs as the second seed in the Western Conference, but were upset in six games by the San Antonio Spurs in the first round.

[15] On January 4, 2011, Butler was ruled out for the rest of the 2010–11 season after undergoing surgery to repair a ruptured right patellar tendon.

[18] On August 29, 2013, the Suns traded Butler to the Milwaukee Bucks for Ish Smith and Viacheslav Kravtsov.

[19] On November 22, Butler scored a game-leading 38 points, his largest single game total since 2009, during an overtime 115–107 loss to the Philadelphia 76ers.

[23][24] On June 11, 2015, Butler was traded, along with Shawne Williams, to the Milwaukee Bucks in exchange for Ersan İlyasova.

[29] Butler's final NBA game was on April 11, 2016, in a 105 - 101 victory over the Phoenix Suns where he recorded 7 points, 2 rebounds, 1 assist and 1 block.

'"[35] Butler attended a surprise birthday party for Anthony Fadel, a 16-year-old in the Washington, D.C. area when invited by the boy's family.

[37] After working at Burger King in his youth, Butler now owns six of the fast food restaurants across the United States.