Birley was born in Bromsgrove, Worcestershire. He trained in Birmingham City's Academy set-up and was a regular in the Reserve side in the 2004–05 season. He held a one-year professional contract in the summer of 2005, which was extended for a further year in 2006.
Birley is a midfielder who can play on either wing and also scored several goals while in the Reserves, including the opening goal in the 2005 Birmingham Senior Cup final.
On 26 October 2005, he made his professional debut in the third round of the League Cup, replacing Mikael Forssell for the final 14 minutes of a 2–1 home win over Norwich City. Birley made his only Premier League appearance on 31 December, when he came on as a 65th-minute substitute for Emile Heskey in the match against Chelsea at Stamford Bridge that resulted in a 2–0 win for the London side. His only other game for Birmingham was on 7 February 2006 in an FA Cup fourth round replay against Reading, starting and making way for Mat Sadler after 59 minutes of an eventual 2–1 win.
On 23 November 2006 he joined League Two team Lincoln City on loan, debuting in the 2–1 defeat at Wrexham two days later. He made three more appearances for the Sincil Bank club before returning to Birmingham in January.
In May 2007, he underwent a trial at A.F.C. Bournemouth where he featured for the reserve team. On 14 May 2007 he was released from his contract at Birmingham City.
Birley later signed for Southern League Premier Division club Bromsgrove Rovers and scored on his debut for the club during their League game at home to Mangotsfield United.
In October 2008 Birley joined Conference North side Tamworth. He made his debut coming on as an 81st-minute substitute for Gareth Sheldon in the team's 4–1 away win at Workington on 18 October.
In June 2009, he moved to Northern Premier League Premier Division team King's Lynn, debuting in the 1–3 home defeat to Stocksbridge Park Steels on 15 August. He departed the club following the 2–1 away defeat to Buxton on 14 September with Lynn's manager Carl Heggs claiming that he had been released for "not producing", although Birley claimed it with his decision due to the length of commute from his home in Bromsgrove to Norfolk. He quickly linked up with Conference South team Worcester City, debuting in the 1–2 home defeat to Thurrock on 19 September.
On 16 May 2013, Birley and teammate Rob Elvins left Worcester for Conference North club Solihull Moors.
After a couple of years out of the game due to a groin injury, Birley linked up with Worcester City ahead of the 2016-17 season who retained his registration whilst Birley played for Halesowen Town. In May 2017 he rejoined Worcester City.