Neill played as a defender, often playing as a centre back as well as a full back. Neill spent almost 15 years of his career playing in England. He represented Australia at the 2006 FIFA World Cup, the 2007 AFC Asian Cup, the 2010 FIFA World Cup in South Africa, and also the 2011 AFC Asian Cup in Qatar. On 6 October 2006 he was named the 50th captain of the Australian national team. He also played for Millwall, Blackburn Rovers, West Ham United, Everton, Galatasaray, Al Jazira, Al Wasl, Sydney FC, Omiya Ardija, Watford FC and Doncaster Rovers.