Born 18 April 1979 in Blackburn, England, Balshaw was educated at the Jesuit Stonyhurst College, at junior level he played for Preston Grasshoppers and joined Bath as a teenager in 1997. He made his senior debut in 1998, scoring thirteen tries in his first season.
Balshaw was picked on the replacements’ bench for every one of Englands internationals in 2000. He won his first cap for England in 2000 at the inaugural Six Nations Championship match against Ireland, coming on as a substitute. In November 2000, he came on late in the England-Australia autumn International at Twickenham to give Dan Luger a last minute winning try.
In the following 2001 Six Nations he finally made the starting line-up for England at full back and stunned the Welsh in the opening game at the Millennium Stadium; England winning 44–15. He toured Australia with the British and Irish Lions in June 2001, but did not start in the Test matches.
However, the 2002/2003 season saw him as a member of the England squad for the tour of New Zealand and Australia, before joining the party for Churchill Cup matches in North America. He scored two tries in a 'non-cap' international against Japan in Tokyo in June 2002, having recovered from shoulder surgery that restricted him to nine games in the previous eleven months for Bath. Problems with injury meant that his subsequent international appearances were few, despite criticism Clive Woodward retained faith in his ability and selected him to tour in the 2003 Rugby World Cup.
Balshaw played in the warm-up match against France in Marseille and impressed in England's World Cup game against Samoa when he caught a diagonal kick from Jonny Wilkinson to score a crucial try in the 70th minute. He was one of 19 England players who took to the field during the 2003 World Cup final win over Australia in Sydney coming on as a replacement in extra time. In the 2005 Lions tour of New Zealand he was selected ahead of Kevin Morgan and Mark Cueto, but later ruled out with a torn thigh muscle. Balshaw was selected for England in both Tests in Australia in June 2006. He played well although was criticised by the media for chipping out of his own 22.
He was also chosen in the first two Autumn Internationals in 2006. He played against New Zealand and then against Argentina where he scored an individual try. However, he then pulled out of the 1st Test against South Africa injured.
He was England's first choice Fullback during the 2008 Six Nations Championship but received a lot of criticism from rugby pundits including George Hook. When Martin Johnson announced his first England squads in July 2008 following his appointment as manager, Balshaw was omitted from both the Elite and Saxon selections. As of 2011 Balshaw looks unlikely to make his way back into the squad at fullback, with Ben Foden and Delon Armitage being the regular choices, as well as Mark Cueto's ability to cover the position and the rise of Saxons stars Alex Goode and Mike Brown.
After Balshaw's move to Leeds in July 2004, his game at club level flourished. Balshaw was out of action for the beginning of the season with a groin injury, but after three months of work with the Leeds medical staff he was back to fitness. He made his debut off the bench in the Tykes first home win of the season against Worcester Warriors. Balshaw's first start came away against Grenoble in the European Challenge Cup and he has featured in the starting line up for the Tykes subsequent games. After a run of five impressive starts Balshaw was rewarded with the captaincy for the Powergen Cup semi-final game against London Irish, and this performance saw him gain a recall to the England squad. He started the final itself, however he limped off injured early on in the game as his team mates went on to win the trophy.
Following Leeds Carnegie relegation from the Guinness Premiership, in April 2006, Balshaw joined Gloucester Rugby in his debut against old club Bath after making 106 Premiership appearances for Bath and Leeds scoring 38 tries.
Balshaw moved to Biarritz Olympique in 2009, as part of a large exodus of English players to the French Top 14.
On 11 July 2014, Balshaw announces his retirement from rugby with immediate effect after failing to recover from his knee injuries.
Balshaw is married to Kate and they have three children. Since 2013 Iain Balshaw has been running a Rugby fanzine website called www.rugbypigs.comPowergen Cup/Anglo-Welsh Cup titles: 1
Amlin Trophy Championship Winner 2012Rugby World Cup Winner 2003