Having previously represented the province at under-18 level, as well as playing for Munster's 7s team in the IRFU's inaugural HPC Sevens Series and for the 'A' team in fixtures against Leinster A and Ulster A, Donnelly joined the Munster academy ahead of the 2021–22 season.[3] Following the disruption caused by the province's recent tour to South Africa, Donnelly made his senior competitive debut for Munster in their opening 2021–22 Champions Cup fixture away to English club Wasps on 12 December 2021, coming on as a replacement for Dave Kilcoyne in the province's 35–14 win.[4] Donnelly made his league debut for Munster as a replacement for Josh Wycherley in the province's 29–24 away defeat against South African side the Bulls in a rescheduled round 6 fixture during the 2021–22 United Rugby Championship on 12 March 2022.[5]