Tom Beahon grew up near Bebington on the Wirral. He played youth football at Tranmere Rovers from 17 to 21, then played in Spain and spent time at the Glenn Hoddle Academy. His brother Phil played semi-professional cricket in Cheshire and Lancashire.
In 2013 both brothers quit playing. Tom took a job at Lloyds Bank in London and Phil joined Deloitte. The jobs were a way to save money and make contacts for a sportswear brand. Before launch they interviewed gym-goers and signed investors from fashion and sport.
They set up Castore in Bebington in 2015 and launched online in 2016. Andy Murray became a shareholder in March 2019 and Tom and Phil made the Forbes 30 Under 30 list that year. In 2020 Castore signed Rangers in a deal of about £25 million over five years, which moved it from gym wear into team kit.
Growth brought complaints. Rangers fans criticised kit mix-ups, and Aston Villa players said their shirts felt heavy when wet. Villa moved to Adidas in January 2024. Castore bought Belstaff in 2025 and Grenson in 2026, and in October 2026 JPMorgan was advising it amid sale approaches.