As a teen, Tinsley developed his game playing streetball at New York City's Rucker Park.

San Jacinto Community College (MSJC) before breaking onto the national scene in the Big 12 Conference at Iowa State University.

The team, along with fellow star Marcus Fizer, reached the Elite Eight before losing to eventual champion Michigan State.

[3] Tinsley spent the majority of the 2004–05 season on injured reserve due to a bruised left foot, but the team played its way to a 44–38 record and the sixth seed in the Eastern Conference.

[3] Tinsley's injury problems continued during the 2007–08 season; he only played in 39 games, during which he averaged a career-high 8.4 assists.

"[8] The Grizzlies did not guarantee Tinsley a starting spot, but told him he would be allowed to compete for the point guard position.

On November 3, 2011, Tinsley was picked 1st overall by the Los Angeles D-Fenders in the NBA Development League Draft.

On November 16, 2001, just in his 11th rookie game, Jamaal posted a rare 5 x 5 against the Minnesota Timberwolves, with 12 points, 9 rebounds, 15 assists, 6 steals and 5 blocks.