Josh started his career with Arsenal, joining the team’s Hale End Academy at the age of 8. He joined the club on a professional contract in August 2015 and spent the next two years playing for the first team. He appeared three times for the team, all of them in EFL Cup games.

Josh signed a four-year contract to join Brentford in 2018. He got his first game in action in a 2-0 victory over Millwall, coming on as a substitute. In the rematch against Millwall in April 2019, he scored his first goal as a senior with an amazing curling effort into the upper corner.