He first began playing rugby with Ennis, forming a half-back partnership with fellow Munster academy member Ethan Coughlan and captaining the club at underage level.

[1] As well as rugby, Butler was a talented hurler for St Joseph's Doora-Barefield, and started for Clare in their defeat against Limerick in the 2019 Munster Minor Hurling Championship final.

He also helped St Flannan's win their first Dr Harty Cup in 15 years in March 2020.

[3] Butler was registered with Munster's Champions Cup squad in December 2021 following the disruption caused by the province's recent tour to South Africa,[4] and made his senior competitive debut for the province in their opening 2021–22 Champions Cup fixture away to English club Wasps on 12 December 2021, coming on as a replacement for Joey Carbery in the province's 35–14 win,[5] alongside fellow Ennis RFC men Ethan Coughlan and Conor Moloney.

[6] Butler was selected in the Ireland under-20s squad for the 2022 Six Nations Under 20s Championship when it was announced in January 2022,[7] and made his competitive debut for the under-20s in their tournament-opening 53–5 win against Wales on 4 February, coming on for starting fly-half Charlie Tector in the 52nd minute and converting Ben Brownlee's 79th minute try.