[2] On the basis of these performances, both Ulster and Connacht showed interest,[3] aware he qualified to play for Ireland through his Irish grandparents.

[4] Both teams offered him a two-year development contract, but Herring asked for a six-month trial so he could continue his studies if it didn't work out, and Ulster agreed.

[4] He was named captain in Best's absence during the 2015 Rugby World Cup,[6] and shared the captaincy with Andrew Trimble during the 2016–17 season after Best stepped down from the role.

On 16 October 2019, Herring was called into the Ireland squad for the 2019 Rugby World Cup to replace the injured Seán Cronin.

[14] Herring represented Ireland at the 2023 Rugby World Cup, where he scored two tries in the pool stage against Romania and Tonga.