Van Horn played for the New Jersey Nets, Philadelphia 76ers, New York Knicks, Milwaukee Bucks, and the Dallas Mavericks of the National Basketball Association (NBA).

A forward, Van Horn finished his college basketball career with the Utah Utes as the all-time leading scorer in the history of the Western Athletic Conference (WAC).

[3] In Van Horn's first season, he averaged a Utah-freshman record 18.3 points on 51 percent shooting and 8.3 rebounds per game even though his father died during his freshman year.

[4] In 1997, he shot 90.4 percent from the free throw line and averaged 22.0 points and 9.5 rebounds per game to lead the Utes to a 29–4 finish and #2 national ranking, the highest in school history.

As a senior in 1997, he was a consensus first team All American selection[5] and was named ESPN Men's College Player of the Year.

That season, on March 26, Van Horn blocked a career-high 6 shots, along with scoring 22 points, during a 100–91 loss to the Indiana Pacers.

[citation needed] In the deciding Game 5 of their first round matchup with the Pacers, Van Horn scored a postseason career-high 27 points during a 120–109 victory.

[citation needed] On August 6, 2002, Van Horn was traded to the team who initially drafted him, the Philadelphia 76ers, along with Todd MacCulloch for center Dikembe Mutombo.

[14] After spending a year with the 76ers, Van Horn was traded to the New York Knicks for Latrell Sprewell in a four team deal that also included the Atlanta Hawks and Minnesota Timberwolves.

[16] On March 21, 2004, Van Horn scored his highest single game total in Milwaukee, 32 points during a 104–103 loss to the Lakers.

[17] In order to make salary cap room for the signing of free-agent-to-be Michael Redd in the coming off-season, on February 24, 2005, the Bucks traded Van Horn to the Dallas Mavericks for the expiring contracts of Alan Henderson, Calvin Booth and cash.