Alfie Kilgour returned to Bristol from Mansfield Town in June 2025, signing a two-year contract with the Gas.  

Kilgour began his career in the Rovers Academy at age eight and worked through the youth set-up before earning his spot in the first team in a League Two fixture away to Scunthorpe United in August 2016. Within the 2016/17 season, he went out on short loans to Mangotsfield United and Cirencester Town. After injury, the defender joined Hungerford Town on loan in March 2018.

In November 2018, Kilgour joined Maidenhead United on loan and debuted in their FA Cup game at home to Portsmouth, featuring 17 times in all competitions, before being recalled to Rovers in March 2019.

The centre-back made his debut in the blue-and-white quarters in an away win against Gillingham Town. At the end of the 2018–19 season, Kilgour was awarded Bristol Rovers Development Squad Player of the Season.

He continued his campaign with the Gas and made 45 appearances in all competitions in the 2019/20 season and 44 outings in the 2020/21 season, before registering his 100th competitive appearance for the Pirates in a draw against Bradford City in October 2021.

In January 2023, the Kilgour departed Rovers and transferred to Mansfield Town, making 46 competitive appearances for the Stags across two and a half years, before rejoining the Rovers in the summer.