[3] Born in Consett, County Durham, of a Scottish steel-working father and an English mother (Luke and Mary Ann Conlin), Jimmy and his three younger siblings were raised in the Lanarkshire area east of Glasgow often referred to as Old Monkland.
[10] On 14 March 1901, Conlin transferred from Falkirk to Albion Rovers[11] (his hometown club, who played in the Scottish Football Combination League), at which point his career and national notoriety as a highly talented left winger began to take off.
He was at the centre of an infamous incident involving Manchester United's right full back, Bob Bonthron, in a 1–5 home defeat played on 10 February 1906 during the latter club's promotion season.
[3] His debut for the Sky Blues, against Woolwich Arsenal on 1 September 1906, was played during a freak national heatwave in temperatures of 91 °F (33 °C) in the shade and 125 °F (52 °C) in the direct sun, the match saw several players retiring from the game due to heat exhaustion.
Conlin himself was one of two City players who collapsed from the heat during the first half; however, he gamely returned for the second period of play with a knotted handkerchief on his head to better protect himself from the sun, but was still unable to help his depleted side from losing 1–4.
In his fourth season with the Sky Blues in 1909–10, Conlin was a Second Division championship winner as Manchester City immediately returned to the top flight.
On 30 July 1912, Conlin moved on again for a transfer fee of £150, this time returning to Lanarkshire where he was raised to play for Airdrieonians in the Scottish League Division One.
[3] On 13 August 1913 Conlin made his final club transfer, joining Broxburn United who had finished bottom of the Central Football League in the previous season.
[19] At the outbreak of the Great War, Conlin enlisted in Coatbridge with the Highland Light Infantry, serving in the 15th (Service) Battalion (1st Glasgow).
During June 1917 this battalion was transferred to the Nieuport sector on the Belgium coast in readiness to support the British offensive at the Third Battle of Ypres (also known as Passchendaele).