Crean joined the Saracens junior academy in 2015 and then graduated up to the senior academy in 2018, when he spent time out on loan at Bishop's Stortford for the 2018–19 National League 1 season.[2] He initially played as a hooker, before transitioning into the role of loosehead prop.[1] He was also involved in the Saracens Storm squad that won the Premiership Rugby Shield that season, including the 55–14 final victory over Newcastle Falcons A in 2019.[2] His first-team debut arrived in the following season, making several appearances in the Premiership and Premiership Rugby Cup, as well as a single Champions Cup fixture against Racing 92.[1]
Over the next two years, Crean was dual-registered with both Saracens and Ampthill, with the majority of his matches played for the latter club in the RFU Championship.[3] Subsequently, he was promoted into the Saracens first-team squad on a full-time basis, ahead of the beginning of the 2022–23 season.[4]
Crean has represented England at age-group level. He played two games for the England U20s during the abridged 2020 Six Nations, making his debut in a defeat to Ireland and then scoring a try against Wales.[3][5]
Crean joined Ulster on a short-term loan deal in February 2025,[6] and signed for them on a permanent basis from the 2025–26 season.[7] He also qualifies to represent Ireland through ancestry and in February 2026 made his first appearance for Ireland A.[8][9]