Born in Nottingham, Leon started his career at Southampton, making his senior debut against the Magpies on his 18th birthday in September 2004.
A month-long loan spell at Queens Park Rangers followed later in the 2004-05 season, before Leon returned to the south-coast club and helped their youth team reach the final of the 2005 FA Youth Cup.
Leon was loaned out again in 2005-06, twice to Sheffield Wednesday, where he scored his first senior goal – the Owls’ first of the season – at home to Hull City in August 2005, as well as Wednesday’s last of the campaign, away to Derby County in April 2006.
Further loan spells followed in 2006-07, with Bournemouth and Yeovil Town, before Leon returned to play a pivotal role in helping Southampton reach the Championship play-offs, which they lost to Derby County at the semi-final stage.
In July 2007, Leon left Southampton, where he had scored four goals in just eight league starts, to join Coventry City.
Working under Coventry’s new management team of former Rovers defender Chris Coleman and current manager Steve Kean, Leon scored nine goals in his maiden campaign at the Ricoh Arena.
He netted a further four times the following season, including the winner against Rovers in an FA Cup fifth round replay, whilst wearing a protective mask. His international bow came at the end of that season, in a 1-1 draw against Nigeria, and he has gone on to earn seven caps for his country.
After scoring 10 times in the first half of the 2009-10 season, Leon made a January deadline day move to Newcastle United. Injuries interrupted the early stages of his time on Tyneside, but he bounced back with a bang – scoring a stunning hat-trick on his full Premier League debut for the club in a 5-0 win against West Ham in January 2011.
Last season, the pacey frontman netted a further four goals for the Magpies – his last coming against QPR in January. Leon missed the final three months of the season due to a knee injury, which also ruined his chances of representing the Republic of Ireland at Euro 2012.
Unfortunately for Leon after a bright start to pre-season, the striker sustained a cruciate knee ligament injury and will be out of action until the turn of the year.