[5] At the beginning of the 2011–12 Pro 12 League season Leinster had 14 players unavailable for selection as they were representing Ireland in the 2011 Rugby World Cup.

The match was a 19–23 home defeat against Scottish side Glasgow Warriors with Murphy coming on as substitute in the 45th minute replacing Dominic Ryan.

[11] On 15 December 2012, he made his Heineken Cup debut late on against Clermont Auvergne, replacing injured team-mate Shane Jennings.

[12] Towards the end of the season he was named Powerade Young Player of the Year at Leinster Rugby's Annual Awards Ceremony held at the Mansion House in Dublin.

[13] Only a matter of days later Murphy captained Leinster 'A' to victory over Newcastle Falcons in the final of the British and Irish Cup.

He was a member of Ireland's successful 2015 Six Nations squad, starting in two test matches (Italy, England) and coming on as a replacement against France, Wales and Scotland during that campaign.

Murphy scored Ireland's first try in the historic 40–29 defeat of New Zealand – then back-to-back world champions – on 5 November 2016 at Soldier Field, Chicago, but was stretchered off later in the game with what proved to be an ACL injury to his left knee.

[23] Despite returning to the national team, scoring a try in the final warm-up game (against Italy)[24] prior to the 2019 Rugby World Cup, coach Joe Schmidt did not select Murphy as part of the squad for Japan, opting instead to fill the final back-row slot with Murphy's former Leinster teammate, Rhys Ruddock.