During his loan spell at Hull City, Campbell received his first call-up to the England under-21 team, coming on as a substitute in a match against Poland on 25 March 2008. He scored his first international goal on 18 November 2008 in a 2–0 victory over the Czech Republic Under-21s. He also scored in the second group match of the 2009 UEFA European Under-21 Championship against Spain, in a 2–0 victory on 18 June 2009. He was sent off in the semi-final of the championship against Sweden. Following his under-21 experience, Campbell's Sunderland manager Steve Bruce urged Fabio Capello to consider Campbell for promotion to the senior squad saying, "the England manager should have a look at him", also saying "As for England, why not? Why not go with up-and-coming young talent?"