Healy is a member of an elite group of players to have won the European Cup four times, alongside teammates, Devin Toner, Johnny Sexton and Isa Nacewa.

[12][13] On 21 June 2009, he was part of the Ireland 'A' team that won the 2009 Churchill Cup against England Saxons by 49–22 in the final in Colorado.

[15][16] In November 2009, he made his international debut in the test against Australia at Croke Park, and was praised afterwards by coach Declan Kidney for his performance.

Healy was named Man of the Match in a bruising encounter on 17 September 2011, when Ireland defeated Australia 15–6 at the 2011 Rugby World Cup in Eden Park.

[19] Healy was cited to appear before a disciplinary hearing in London on 13 February 2013, where he received a three-week suspension for stamping on the ankle of opponent player Dan Cole during Ireland's second round encounter with England in the Six Nations Championship.

[20] Healy was a key member of the Grand Slam winning Ireland team during the 2018 Six Nations Championship, starting four of the five games including the decider against England in Twickenham.