In 1907 the club were founder members of the Spartan League and went on to become its inaugural champions. They joined the Isthmian League for the following season, and won back-to-back titles in 1908–09 and 1909–10. In 1910–11 the club won the FA Amateur Cup, beating Bishop Auckland 1–0 in the final. The season also saw them finish seventh in 1910–11, the club returned to the Kent League and were placed in Division One. They remained in the league until World War I, but joined the Athenian League when football resumed in 1919. The club were Athenian League champions in 1922–23. In 1937–38 they reached the first round of the FA Cup for the first time. After beating King's Lynn in the first round, they lost 4–1 at Scarborough in the second. They also reached the final of the FA Amateur Cup again, beating Erith & Belvedere 1–0. The club repeated the feat the following season, this time playing Football League opposition for the first time as they lost 8–1 at Lincoln City in the second round. In 1945–46 another second round appearance resulted in a 4–2 aggregate defeat to Watford. In 1947–48 they held Reading to a 1–1 draw in the first round, before losing the replay at Elm Park 3–0.