Morrison arrived at Gonzaga University to play for the Gonzaga Bulldogs in 2003. In his freshman year he averaged 11.4 points per game (ppg), with a season-high 22 points against St. Mary’s. Gonzaga won the West Coast Conference (WCC) regular-season title. Morrison was named to the WCC All-Freshman Team.

In his junior year during Gonzaga’s first two games of the 2005–06 season at the Maui Invitational, Morrison played well against two of the sport’s top programs. In the first round, Morrison scored 25 points in a Gonzaga win over Maryland. He followed up this performance with 43 points in a triple-overtime win over Michigan State in the semifinals. He matched that output against in-state rival Washington on December 4, 2005, in a losing effort. However, Morrison and the Zags bounced back a week later, defeating Oklahoma State after he banked in a three-pointer with 2.5 seconds left to give Gonzaga a two-point lead and eventually the win.

Morrison led the Zags with 24 points in a 2006 NCAA Tournament Sweet Sixteen match against UCLA, which the Zags lost in the final seconds after UCLA had eliminated a 17-point deficit coming out of the first half. With seconds left, the lead having slipped away after Morrison’s teammates committed 3 turnovers in less than 5 seconds, Morrison broke down in tears and collapsed to the court. He was eventually helped to his feet by UCLA player Arron Afflalo. He has been both criticized and praised for this unbridled show of emotion. He later shared the national player of the year award with friendly rival J. J. Redick of Duke. The game against UCLA turned out to be Morrison’s final collegiate game, as he later decided to turn pro, foregoing his senior year of college.

Morrison was selected 3rd overall pick in the 2006 NBA draft by the Charlotte Bobcats, behind Andrea Bargnani (Toronto Raptors) and LaMarcus Aldridge (Chicago Bulls). On July 6, 2006, the Bobcats signed Morrison to a two-year contract. On November 1, 2006, in his NBA debut against the Indiana Pacers he scored 14 points. He was the first player drafted by Manager of Basketball Operations Michael Jordan in his tenure with the Bobcats. He scored his career high on December 30, 2006, with 30 points in a win against the Indiana Pacers. However, Morrison lost his starting spot midway through his rookie season, in part because of his defense and in part because he shot only 37% for the year.

On October 21, 2007, the Charlotte Bobcats announced that Morrison had sustained a severe injury to his left knee in a pre-season exhibition game against the L.A. Lakers while defending Luke Walton, bending his knee laterally and falling to the ground in pain. An MRI scan performed after the game indicated a torn anterior cruciate ligament (ACL). On November 10 Morrison underwent surgery to repair the damage. The injury was confirmed to be a torn ACL, requiring several months of physical therapy after the knee had healed, meaning he missed the whole 2007–08 NBA season.

On February 7, 2009, Morrison and Shannon Brown were traded to the Los Angeles Lakers for Vladimir Radmanović. Morrison won NBA championships with the Lakers in 2009 and 2010, but saw very limited playing time. He was released following the 2009–10 season.

Morrison signed with the Washington Wizards in 2010, but was waived at the end of training camp before playing a regular season game.

In September 2011, Morrison signed with KK Crvena zvezda. He was released from his contract in November 2011 to pursue other opportunities. During his 8-game stay in Belgrade (he missed one away game due to a minor injury), Morrison averaged 15.5 points, 3.1 rebounds and 1.5 assists in 29 minutes a game, becoming his team’s top scorer and the second overall top performer during the 2011–12 Adriatic League season.

In January 2012, Morrison signed with Beşiktaş Milangaz for the rest of the 2011–12 season. However, he left the team in April 2012 due to a lack of playing time.

After being absent from the NBA since being waived by the Wizards, Morrison played in the 2012 NBA Summer League for the Brooklyn Nets and averaged 5.2 points and 19.2 minutes in five games with the team. He then joined the Los Angeles Clippers’ Summer League team, averaging 20.0 points, 5.0 rebounds and 1.0 assists on 55% FG (38–69), 61% 3-PT (13–21) and 78% FT (11–14) in 5 games.

On September 21, 2012, Morrison signed with the Portland Trail Blazers. He was waived on October 27, 2012.

In July 2013, Gonzaga basketball coach Mark Few announced that Morrison would become a student assistant with the basketball team. Morrison had returned to Gonzaga to take classes. After completing his undergraduate degree at Gonzaga in 2014, majoring in sports management, Morrison became an assistant video coordinator for the Bulldogs for the 2014–15 season, but was weighing options for his career after the season would come to an end.