Paul Hayes is the younger brother of former Arsenal and Celtic forward Martin Hayes, Paul is described as natural goalscorer with happy knack of being in the right place at the right time. He hails from Essex and was with Norwich since the age of 13. He had an excellent pre-season in the summer of 2001 scoring five at Wroxham, one at Colchester and one at Carrow Road against Premiership giants Arsenal. Sammy Morgan however said the youngster still had work to do: "Hayes is a good goalscorer, he has good movement and a good touch. I, as an ex centre-forward, continually question him about his bravery. He's got lots of technical quality but I am demanding more from him in terms of getting into the box and being a brave number nine with a good work ethic. If he does that he's got a chance because he's got the technical quality."

Despite sitting on the bench for the final two league games of 2001/02 (vs Barnsley and Stockport) and participating in pre-season friendlies, Paul became frustrated at his lack of first team opportunities, Paul agreed to join Torquay United on 22nd October 2002 on a week's trial. Nigel Worthington intended for him to "toughen up" both physically in Division Three and mentally, by playing for a club whose premises and infrastructure was less developed than at Carrow Road. "We've sent him to Torquay to show him the other side of life and to get him roughed up a bit," said Worthington. "He's a big, strong centre-forward, he's a little bit soft so he can go and experience the delights of lower league football and maybe he'll come back and appreciate the surroundings and the quality that he has here." Worthington confirmed Hayes was not on a loan deal but would be in consultation with the Gulls over whether it would be possible for the 19-year-old to play a competitive match for them.

On 3rd December 2002, Norwich released Paul from his Academy contract as his opportunites at Carrow Road would be limited. He had also been trialling with Scunthorpe and his contract was passed to them. This was recorded as a free transfer although a substantial sell-on clause had been included.

He scored on his debut for Scunthorpe against Southend after coming on as substitute. After scoring a wonder goal against Hull on his full debut and then scoring two goals for Scunthorpe against Rochdale on March 19th 2003, Scunthorpe decided to offer Paul a new deal as a full-time professional rather than as a youth team player.

At Christmas 2004, he was the second-leading scorer in League Two and as such had gained the interest of Championship sides Brighton, Derby, Nottingham Forest and Sheffield United. Barnsley manager Andy Ritchie was also said to have watched him in May 2005 with Hayes mulling over a new three year contract offer from promoted Scunthorpe. Paul eventually signed for Barnsley on 2nd June 2005.

Paul scored for Barnsley in their League One play-off final against Swansea at the Millennium Stadium on 27th May 2006, which finished 2-2 but which the Tykes, also featuring Paul Heckingbottom, won on penalties with the two Pauls both scoring penalties. Swansea did not field either Darren Way or Adrian Forbes.

Although Hayes has started 26 games for Barnsley during 2006/7, scoring five times, he had slipped down the Oakwell pecking order following Istvan Ferenczi's arrival. He was therefore allowed to join Huddersfield on loan on 23rd February 2007 with view to a permanent move in the summer.

Paul returned to Scunthorpe in June 2007 on a three-year deal with the fee set to be decided by a tribunal. Unfortunately Hayes couldn't help Scunthorpe avoid relegation to League One in 2007/8 although they returned to the Championship the following season.

In March 2010, it was reported that Norwich's scouts had been watching Hayes ahead of a possible return to Carrow Road.Instead he transferred to Preston at the end of the 2009/10 season on 10th May 2010

Hayes signed on loan for Barnsley on 28th October 2010, having made only 6 starts since joining Preston. He wass loaned to Barnsley as part of the deal that took Canadian international Iain Hume to Deepdale. Hayes will stay at Barnsley, managed by Mark Robins, until 1st January 2011.

In December 2010, Paul was linked by Sporting Life with a return to Scunthorpe. Scunthorpe manager Ian Baraclough admitted he would welcome back Paul Hayes for a third spell at the club. "If there was a chance to bring him back and he wanted to come back then of course I would be interested," said the Iron boss.

Hayes made 2 appearances for Barnsley before returning to Preston and the starting line-up for the clash at Leicester on 15th January 2001. Paul and Preston were relegated to League One on 25th April 2011 following a 1-0 home defeat to Cardiff.

Released by Preston by mutual consent in June 2011, Paul signed for Charlton on 21st June 2011 on a three year contract. Paul had made 26 appearances for Preston, scoring four times.

On 24th February 2012, Hayes and teammate Gary Doherty oined Wycombe on loan until the end of the 2011/12 season. Hayes jad scored three times in 17 appearances for the Addicks during the season to date. Unfortunately they could not help Wycombe avoid relegation to League Two when they lost 4-3 to Notts County on 28th April 2012

Paul was allowed to join Brentford on a free transfer on 20th August 2012.

Hayes joined Crawley on a one month loan on 11th March 2012. The 29-year-old has moved away from Griffin Park despite making 30 appearances and scoring six goals in his first season at the club.

In October 2013, he was loaned out again, joining Plymouth on a month's loan on 4th October 2013. On returning to Brentford, he was released by mutual consent on 4th December 2013. He trialled with Crawley in December 2013 and then joined Scunthorpe for a third time on 17th December 2013 although he was not available for the Iron until 4 January because of the registration deadline.

Hayes and Scunthorpe won promotion to League One on 26th April 2014. Hayes was released at the end of the season but by mid-May had signed for Wycombe Wanderers.

Released by Wycombe in August 2017 having scored 19 goals in 100 games. He signed for Conference South side Hemel Hempstead Town on 22nd September 2017.

He returned to league football on 1st October 2017 signing for Newport County. He made 13 appearances, 10 of which were as substitute. He was released on 9th May 2018.

On 9th August 2018, he signed a two year deal with Isthmian League side AFC Sudbury. He has since played for Romford and Meridian VP before joining Isthmian Leadue side Faversham Town on 7th January 2020.

He has also formed his own football agency called Lineos Players Services.

He joined Chatham Town as player/sporting director in March 2020. On 1st May 2022 he was appointed Sporting Director of Isthmian League side Bowers & Pitsea.