He took his diagnosis surprisingly well; the second time a nurse came to administer insulin, he stopped her, telling her, "Since I'm going to be doing this the rest of my life, you might as well show me how to do it.

In his senior year he broke single-season and career scoring records in his high school conference, and led Mead to the finals of the state tournament.

He scored a season-high 28 points at home against San Francisco, including the winning shot with 0.6 seconds to play in the game.

[5] 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.

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.

On February 18, Morrison recorded a career high 44 points (including 37 in the second half alone) against the Loyola Marymount Lions in a winning effort.

He later shared the national player of the year award with friendly rival JJ Redick of Duke.

Morrison was selected third overall in the 2006 NBA draft by the Charlotte Bobcats, behind Andrea Bargnani (Toronto Raptors) and LaMarcus Aldridge (Chicago Bulls).

However, Morrison lost his starting spot midway through his rookie season, in part because of his defense and because he shot only 37% for the year.

The injury was confirmed to be a torn ACL, requiring several months of physical therapy after the knee had healed, and Morrison missed the whole 2007–08 NBA season.

Following their 2010 Finals win over the Boston Celtics, several Lakers players appeared on the Jimmy Kimmel Show and clips were shown of Morrison merely watching on the bench or joining in the championship celebration.

[14] Morrison later recalled building a relationship with Bryant that continued to the end of his career, including being thankful for the star standing up for him in the face of national media.

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

[22] 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.

Morrison was selected to train with the senior men's team in preparation for the 2006 FIBA World Championship but was cut prior to the tournament.

[29][30] Morrison was named the color commentator for the Gonzaga men's basketball radio broadcasts with former KREM 2 sports director Tom Hudson in October 2017.

Morrison, who managed his diabetes to the point of eating exactly the same meals at the same time on game days, is considered a role model for children with the disease and their families.

During his freshman year at Gonzaga, Morrison and his life with diabetes were a subject of a four-page article in Sports Illustrated.