Iain Turner arrived at Goodison in January 2003 in a £50,000 deal from Stirling Albion after making just 13 appearances for the Scottish side, although his debut saw Albion lose 5-1 at Morton on 18 August 2002. Coveted by a number of Premiership clubs including Tottenham and Charlton after impressing for the Scottish Division Three side, David Moyes swooped to sign Turner after he did well during a three-day trial.
Turner made his debut as a second half substitute in the 3-0 friendly win over Bologna in August 2003.[
A loan spell at Chester City during the 2003/04 season gave the young Scot some valuable experience, making 12 appearances and winning a Conference Winners’ medal
Capped at Under-16 and Under-18 level by Scotland, he made 6 appearances for the Scotland Under-21 squad in 2004/05. Turner also had a loan spell with Doncaster on 15 March 2005 until the end of the season making 8 appearances.
A further loan spell at Wycombe followed early in November 2005 for a month, making 3 appearances. The keeper made his Everton debut as a late replacement for the injured Richard Wright in a 4-1 FA Cup fourth round defeat to Chelsea at Stamford Bridge on 8 February 2006.
His Premiership bow came just three days later when he found national fame when he was sent off after only nine minutes during his Premier League debut for the Toffees against Blackburn, after picking up a header from one of his own defenders, Alan Stubbs, outside the penalty area
He replaced Wright on 54 minutes in a 1-0 win at Middlesbrough on 29 April 2006. On the final day of the season, stepping in for the injured Richard Wright and playing 90 minutes of the club's 2-2 draw against West Bromwich Albion.
The 2006/07 season saw Turner join Crystal Palace for a month on 16 November 2006 and made 5 appearances, one of these was a 0-0 draw at Deepdale on 25 November.
On 23 February 2007 Turner moved to Sheffield Wednesday on loan and it proved a hugely successful move. Owls beat Southend 3-2 on 24 February 2007on his debut and remained unbeaten during his 11 game spell with The Owls and manager Brian Laws made no secret of his desire to sign him permanently.
A week after his last Wednesday game on 28 April 2007 he was immediately installed as goalkeeper against Manchester United in place of the ineligible Tim Howard, unfortunately the Toffees lost 4-2 and to date this was the last of his 4 appearances for Everton. Turner also signed a new contract keeping him at Goodison until 2011.
In the same season he received his first call-up to the senior Scotland squad and was part of the squad for the summer Euro 2008 qualifiers.
Turner underwent hip surgery at the start of the 2007/08 season. Turner was back with Everton reserves in the early parts of the 2008/09 season before joining Nottingham Forest on loan on 19 March 2008 with his 3 appearances helping them avoid the drop to League One.
He also played for Scotland 'B' at the end of the season but much of his 2009/10 season was blighted by injury.
In August 2010 he signed on a month emergency loan to Coventry as back-up to Keiren Westwood, making 2 appearances for the Sky Blues. On 9th February 2011, Turner signed for Preston on a 93 day emergency loan.