Intended as a replacement for retired captain Charlie Buchan, Jack was a success at Highbury. He made his debut against Newcastle United on 20 October 1928, and became a regular straight away. He was the club's top scorer for the 1928–29 season. Although less prolific than centre-forward Jack Lambert, he still scored important goals, including the one in the 1929–30 FA Cup semi-final against Hull City which sent Arsenal through to the final, in which Arsenal beat Huddersfield Town 2–0 and Jack became the first player to win the Cup at Wembley with two different clubs. He played in Arsenal's 2–1 victory over Sheffield Wednesday in the Charity Shield at Stamford Bridge in October 1930.