Campbell turned professional in 1982. Playing in only one tournament during the 1982/1983 season - the 1983 World Championship, he defeated Mike Watterson 10–6 in the first qualifying round and Jim Donnelly 10–2 in the second, to reach the main stages at the Crucible Theatrefor the first time. There, he was drawn against former World ChampionCliff Thorburn but lost 5–10. Beginning the next season with a world ranking, placed 39th, Campbell played in five events, the highlight coming at the 1983 Professional Players Tournament, where he overcame Doug Mountjoy, Graham Miles and Dave Martin to reach the quarter-finals. In his match against Tony Knowles, he led 2–0 but could not prevent a 3–5 loss. In his attempt to qualify again for the World Championship, he lost 7–10 to Thorburn's compatriot Marcel Gauvreau. The 1983/1984 season heralded better form still, Campbell reaching the last-32 stage of four tournaments and making his second appearance at the Crucible; in the latter, he defeated another Canadian, Mario Morra, 10–9 - having trailed 6–9 - to qualify, before being eliminated 10–3 by his fellow Australian Eddie Charlton. Campbell beat Charlton in the final of the 1985 Australian Professional Championship, and during 1985/1986 recorded progress to the last-16 at four events. The most notable of these was the 1986 World Championship, where he defeated Jimmy van Rensberg in qualifying, following this with a 10–8 victory over six-time World Champion Ray Reardon in the first round; however, in the next, Willie Thorne beat him 13–9. Campbell's performances in the ensuing few years were good; he reached the final of the 1986 Australian Professional Championship, but lost 3–10 to Warren King, and won the event for the second time in 1988, overcoming Robby Foldvari 9–7. By this time, his ranking had slipped from his peak - at 18th - to 47th, and although he reached the last 16 at the 1990 Asian Open, losing 4–5 to Mark Bennett, he would not make such progress again. Following a 3–10 loss to John Giles in qualifying for the 1993 World Championship, he concluded the 1992/1993 season ranked 65th and did not play competitive snooker thereafter. He was relegated from the tour in 1994.
