Campbell attended the University of Southern California. While a sophomore at USC, he qualified for the 1980 U.S. Olympic team, but was prevented from competing in the 1980 Summer Olympics by the American-led boycott. Campbell was the youngest member of a movement that considered circumventing the U.S. boycott by competing under the International Olympic Committee flag, in an effort to make a statement that politics and sports should not be mixed. However, threats by U.S. officials to revoke athletes's passports and visas caused the effort to fold. Campbell noted that he would have moved forward with the effort if the group had decided to move forward: "For my age and who I was at the time, that would have been the right thing for me to do. In the event that we were banned from coming back to the U.S., I think I would have survived. I've been around the world enough to see some incredibly wonderful places where I could have been very comfortable."
Campbell was one of the most consistent high hurdlers of the 80s. In Track and Field News magazine's world merit rankings, he was ranked in the top ten for eleven consecutive years (1980-90) with his highest placement being number two (in 1987).