Van Horn, a 2:1 underdog, defeated Robert Hines by a 12-round unanimous decision to win the IBF Junior Middleweight Championship on February 5, 1989, in Atlantic City, New Jersey.
[2] On July 15, 1989, Van Horn returned to Atlantic City to make his first title defense against Gianfranco Rosi, the former WBC Super Welterweight Champion.
[4] Van Horn moved up in weight and won the IBF Super Middleweight Championship with an 11th-round knockout of Lindell Holmes in Italy on May 18, 1991.
On January 10, 1992, Van Horn lost the title to Iran Barkley, the former WBC Middleweight Champion, by a second-round technical knockout in New York City.
The Boston Globe reported: "Sadly, word around boxing says his real problem has been near-constant headaches that recently forced him to stay in a darkened room for days at a time."
The Van Horn camp denied that was true, but one fight figure was quoted as saying: "It would be child abuse for his father to put him back in the ring.
Van Horn was scheduled to face Nigel Benn for the WBC Super Middleweight Championship in England on September 10, 1994, but the fight was called off.