Raynor was born in Leeds, West Yorkshire, England, he started his career in rugby union as a centre. He started out at Pontefract RU and later moved onto Castleford Panthers before Leeds Tykes stumbled upon his performances and took a keen interest. It was not long after that he moved to the Tykes in 2000. He made 8 appearances for the Tykes in their Division One season. Raynor left the Tykes in the summer and switched codes to play Rugby league for sister club, Leeds Rhinos.
Professional playing career
2000s
Gareth transferred to Leeds in the summer of 2000 and made three off the bench performances for the Rhinos. With little game time Gareth moved to Hull F.C. on a two-year contract. Injury to established winger Chris Smith led to more starts than expected for Raynor and he soon became a fans' favourite. After the 2002 Super League season, he returned to rugby union and played for the Leicester Tigers. He made four appearances in the 2002–03 season for the Leicester Tigers with two from the substitute bench before leaving to return to rugby league with Hull F.C. midway through the 2003's Super League VIII. Raynor was a regular at Hull F.C. after a successful season on the wing with 18 tries in all competitions at the end of 2005. Raynor played for Hull at centre in the 2005 Challenge Cup final, scoring a try in their victory against the Leeds Rhinos. Hull reached the 2006 Super League Grand final to be contested against St. Helens, and Raynor played on the wing in his side's 4-26 loss. He became a Great Britain international, starring in the 2006 Tri Nations. He was forced to rule himself out contention for the England training squad for the 2008 Rugby League World Cup through injury.
2010s
For 2010's Super League XV, Raynor signed for Crusaders on a short-term deal, pending the results of his upcoming court case. During the opening match of 2010's Super League XV against Leeds Rhinos, Raynor scored Crusaders first try of the season and only try of the match, going on to lose 34–6. Raynor was jailed for 15 months on 17 May 2010 for his part in an eBay ink cartridges and computer games scam and breaching a suspended sentence for assault. Despite a lucrative rugby career Raynors scam netted over £36k. He imported fake ink and Nintendo games cartridges from the Far East and re-packed it. He was caught after a complaint from EPSON ink manufacturers which made test buys from his eBay site. On 16 September 2010 it was confirmed that he had signed a 1-year deal with the Bradford Bulls. Raynor featured in three of the four pre-season games. He played against Halifax, Dewsbury Rams and Wakefield Trinity Wildcats. He scored a try against Halifax. Gareth featured from Round 1 to Round 5. He picked up an injury then returned in Round 10 through to Round 12. Raynor's next game would be Round 14, he was suspended for the next two games. He then played in Round 17. Gareth then played in seven consecutive games from Round 19 until Round 25. Raynor then featured in Round 27. He also appeared in the Challenge Cup games against Halifax and Wigan Warriors during this match he was sent off for punching Sam Tomkins. He scored tries against Huddersfield Giants, Hull Kingston Rovers, Catalans Dragons, Castleford Tigers and Halifax. He signed a 1-year extension with the Bradford Bulls. He was sacked by the Bradford Bulls in the off-season for undisclosed reasons. He signed for the Featherstone Rovers for the 2012 season, but he only played 4-matches, scoring 3-tries. After July 22, 2013 he signed a year-long contract with the London Skolars in the Kingstone Press Championship 1 which proved as quite a shock to all the rugby league admirers. He provided a try 2 minutes into his début for the London Skolars against Oldham.
