*Club domestic league appearances and goals, correct as of 00:01, 8 December 2024 (UTC) ‡ National team caps and goals, correct as of 23:29, 18 January 2021 (UTC)
Happe was drafted into the Leyton Orient first team squad in February 2017, and made his debut and his first senior start in the 3–0 league defeat at Cambridge United on 8 April 2017.[5]
He signed his first professional contract in October 2017, tying him to Leyton Orient until the end of the 2019–20 season.[6] He signed a new contract in July 2019, until 2021.[7] Happe was a member of the Leyton Orient side that won the 2022–23 EFL League Two title.[8][9] In June 2024, he signed a new two-year contract with Orient.[10]