Aston, Birmingham born inside right Pat Flanagan began his football career with Verity’s Athletic and played for Stourbridge in 1906, from where he turned professional with Southern League club Norwich City in 1907. Signed by Second Division club Fulham in the summer of 1909, he made his Football League debut against Blackpool that September, scoring his only goal for The Cottagers in a win over Grimsby Town the following April. Never a regular at Fulham, in December 1910 joined Woolwich Arsenal (both clubs being owned by the same man, Sir Henry Norris, at the time), after 12 appearances for The Cottagers. Flanagan made his Arsenal debut at outside left in an FA Cup defeat at Swindon Town on 4th February 1911 and his League debut for The Gunners followed a week later at inside left against Bradford City; over the next five seasons he played in every forward position but most regularly at inside right.
He was a regular in their 1911-12 campaign but lost his place in February 1913 during their disastrous relegation campaign. During their 1913-14 Second Division campaign he finished as Arsenal’s second top scorer with 12 League goals in the club’s first season at Highbury. Flanagan was a regular for Arsenal until he lost his place towards the end of 1914-15 season a month before peacetime football was suspended in May 1915 due to the onset of the First World War, and he spent the next two seasons as a bit-part player during wartime competition before he retired after an injury in 1917, having scored 28 goals in 121 appearances for Arsenal.
Flanagan enlisted in the British Army under the Derby Scheme in December 1915, before returning to his reserved occupation as an artillery shell machinist at The Royal Arsenal. He was later mobilised into The Army Service Corps in February 1917 and was posted to 816th M.T. Company in German East Africa, now Tanzania. Driver Flanagan died of dysentery at the 52nd (Lowland) Casualty Clearing Station in Mingoyo on 31st August 1917, aged only 27.