Career
Swindon Town
Having spent time playing for various non-League football teams such as AFC Wallingford, Hayes & Yeading United and Windsor & Eton, Gladwin moved in to professional football when Swindon Town signed the midfielder from Marlow in November 2013. Gladwin made his debut for Swindon on 10 December 2013, in a 1-1 draw at home to Stevenage in the Football League Trophy. His first goal for the club came the following season, in a 3-2 loss against Plymouth Argyle in the same competition.
On 11 May 2015 Gladwin scored twice in Swindon 5-5 draw with Sheffield United in the Football League play-offs, but Swindon went on to lose in the final 4-0 against Preston North End.
Queens Park Rangers
On 28 May 2015, Gladwin and Swindon Town teammate Massimo Luongo, joined Queens Park Rangers, both players signing on a three-year deal for an undisclosed fee, reported to be £3.5m.