On 31 August 2000, the then England under-21 manager, Howard Wilkinson, called the 19-year-old into his squad for the match against Georgia.[The game, played at the Riverside Stadium, Middlesbrough, ended in a 6–1 win for the home team. Further appearances for the under-21s followed in friendlies against Italy and Spain.
Hargreaves played his first full international game on 15 August 2001against the Netherlands at White Hart Lane, giving him the distinction of being the only player to appear for England despite having never lived in England. He was also the second player (after Joe Baker) to have appeared for England without having played in English league football and the first to appear for England without having played in Britain. In only his second cap he came on as a substitute as England famously beat Germany 5–1 in the Olympiastadion. Hargreaves was the only player playing outside the Premier League to be selected for England’s 2002 FIFA World Cup squad. Hargreaves was injured after just fifteen minutes of England’s second group game against Argentina and had to be substituted.
Although he had not usually been part of the first-team, he was selected for the England squads at Euro 2004 in Portugal and the 2006 World Cup in Germany despite criticism from sections of the press and public. The generally negative perception of him by English fans had not been helped by his seeming to have an essence of «German-ness», exacerbated by his Canadian accent and fluency in German.While restricted to three appearances as a substitute at Euro 2004, Hargreaves was in the starting lineup of England’s final three matches in 2006. In a tournament in which England were generally regarded as having underachieved, he was, by the end of England’s participation, widely considered one of the few successes of the English squad. He was named Man of the match in the quarter final against Portugal, the game in which England were eliminated after a penalty shootout, Hargreaves having been the only successful English penalty taker. In 2006, he won both England Player of the Year, and England Player of the World Cup in official FA polls, the first to win both in the same year
Hargreaves picked up the Man of the match award in England’s 4–0 win over Greece on 16 August 2006. On 30 January 2007 he was voted England Player of the Year 2006, as voted for by visitors to the Official FA site.
In June 2007, FIFA announced that Hargreaves and Philipp Lahm would visit South Africa in advance support for the 2010 FIFA World Cup.
After his transfer to Manchester City in 2011, England coach Fabio Capello hoped that Hargreaves would regain his fitness saying «I hope he will be really good in the short-term for Manchester City and also for England.»
Hargreaves’ career was affected by injuries, the bulk of which formed in 2006, the year he won the award for England’s best player at the 2006 World Cup. Hargreaves stated that he believed the bulk of his injury problems to have been in 2007, when he returned from injury after breaking his leg. He felt that his muscle in his leg was weaker than before he sustained his broken leg, and initially Hargreaves ignored the aching and played on.