There he was a member of the team that won the 2014 Leinster Schools Senior Cup, with Keenan noted for his running and passing,[2] including scoring a try in the final.

He also started all matches in the 2016 World Rugby under-20 Championship, including Ireland's historic victory over New Zealand.

[10][11] Keenan debuted for Ireland on 24 October 2020 in a Six Nations match against Italy, where he started on the wing and scored two tries in a 50–17 win.

[12] Keenan then started Ireland's next 17 internationals (2020–2022), scoring tries against Georgia, Italy, USA, England and New Zealand.

[14] Known for his defence, aerial skills and cunning ability to pick up loose kicks and engineer attacking plays for his team, 'The Fox' is considered one of the best fullbacks in the world.