Gallacher joined David Calderhead's Chelsea as part of a £25,000 spending spree which also saw the club sign his fellow Scottish forwards Alex Jackson and Alec Cheyne; such was his popularity at Newcastle, when Chelsea visited St James' Park, the home of Newcastle United, that season the attendance was a record 68,386 with several thousand more locked out. Gallacher scored 81 goals in 144 games and was Chelsea's top scorer in each of his four seasons in west London. The team sometimes clicked, such as in a 6–2 win over Manchester United and a 5–0 win over Sunderland but trophies remained elusive.