Doyle was born in Dublin and had a very successful underage career which included playing for the U15 Republic of Ireland national football team.

Following a four-year spell with Dublin club Crumlin United, Doyle returned to Shelbourne who had just been relegated to the League of Ireland First Division.

His time there was cut short and he was released midway through the 2007 season without making his league debut following a disappointing spell for him and the club.

[13] Doyle did not start a game for more than two months, until an appearance against St Mirren in late April, where he missed some chances as Hibs lost 1–0.

[15] BBC Radio Sheffield reported on 3 April 2013 that Doyle had agreed to sign for English Football League Two club Chesterfield.

[16] Shortly after this announcement, Doyle scored the equaliser in the Scottish Cup semi-final, in which Hibernian overcame Falkirk 4–3 after extra time after having initially been behind 3–0.

[18] Doyle said that the presence of manager Paul Cook, who had worked with him at Sligo Rovers, was an important factor in his decision to join Chesterfield.

During the summer of 2017 after returning from an unsuccessful loan spell at Portsmouth, Doyle featured in new Preston North End manager Alex Neil's plans for the 2017–18 season, battling it out with Jordan Hugill and Sean Maguire to lead the line.

[31] He scored 10 goals in 44 games in his debut season with The Bantams On 16 August 2019, Doyle joined fellow League Two side Swindon Town on a year-long loan deal.

[32] In December 2019, he became the first player in any of England's top four leagues to score in eleven consecutive matches since Leicester City's Jamie Vardy in 2015.

[35][36] After scoring three goals in Pre-season,[37][38][39] his competitive debut came on 5 September in Bolton's first match of the season, a 1–2 home defeat against Bradford in the first round of the EFL Cup.

[48] On 11 March 2022, Doyle scored his first league goal for the club by heading home a Chris Forrester free kick to help his side to a 2–0 win away to Finn Harps.

[52] Doyle made his first appearance in European football for the club on 21 July 2022, assisting Chris Forrester's equaliser in a 1–1 draw with Slovenian side NŠ Mura in the UEFA Europa Conference League.

[53] Doyle scored a brace of penalties on 3 October 2022, to help his side to a 4–4 draw having previously trailed 4–2 away to rivals Shelbourne at Tolka Park.

[59] Doyle's final appearance in professional football was on 20 July 2023, in a UEFA Europa League tie at home to F91 Dudelange of Luxembourg.

[60] On 27 July 2023, it was announced that Doyle had retired from professional football at age 35 for personal reasons, after scoring 208 goals in 635 appearances during his career.