Campbell was born in Perth, Western Australia, and played WACA grade cricket for Bayswater-Morley, Scarborough, and Joondalup. He has Hong Kong Chinese ancestry through his grandmother, with one of his great-grandfathers being born in Kowloon. Campbell's wife, Leontina Heffernan Campbell, and son, Jake, were also born in Hong Kong. His brother in law is Andrew Heffernan, who competed in the equestrian events at the 2012 Summer Olympics. Campbell suffered from depression during his playing career, and in 2001 contemplated retiring early to focus on his health, eventually deciding to continue playing. He is a supporter of beyondblue, an Australian mental health advocacy group.

Australia

Campbell was inducted into the Australian Cricket Academy in 1994, and made his first-class debut for an Academy team in April 1995, playing against the New Zealand Cricket Academy. His debut for Western Australia came in February 1996, during the 1995–96 season of the Mercantile Mutual Cup (the national one-day competition). Campbell initially played as a specialist batsman, with Adam Gilchrist serving as wicket-keeper. He did keep wicket on his Sheffield Shield debut (against Tasmania in November 1996), which came in Gilchrist's absence, but spent the remainder of the season as an opening batsman, partnering with Mike Hussey. Campbell was one of only three WA players to appear in every Sheffield Shield match during the 1996–97 season, and finished with 672 runs, behind only Mike Hussey and Justin Langer amongst his teammates. Against Victoria, he scored a maiden first-class century, making 113 runs from 106 balls. He brought up his century in only 86 balls, making it the fastest hundred of the season.

During the 1997–98 Sheffield Shield season, Campbell was again among the leading batsmen for WA, scoring 726 runs from eleven matches. He scored three centuries during the season, including 177 against New South Wales, and also kept wicket in four games while Adam Gilchrist was on national duty. In August 1998, Campbell was selected for Australia A for the first time, touri