He also played over a decade for the Ireland national rugby union team with whom he earned 95 caps, and went on two British & Irish Lions tours in 2009 and 2013.

[4] Kearney attended University College Dublin on a sports scholarship where he played for the rugby team.

In 2005 he helped the U-20s team win the McCorry Cup, beating Dublin University Football Club in the final.

He made 32 appearances in the competition, scoring eight tries, with three penalties during a period in September 2006, when usual place kicker, Felipe Contepomi was injured.

[12] In late September 2020, it was confirmed that Kearney had signed a one-year contract with Australian side Western Force.

[15] Following his retirement, Kearney returned to Louth GAA club Cooley Kickhams where he began training in August 2021 for the first time since 2005.

[17] He was a member of the victorious Ireland team that won the 2009 Six Nations Championship, Triple Crown and Grand Slam.

[19] Kearney missed almost a year – from November 2010 until August 2011 – due to a knee injury that required surgery.

[20] In the 2011 Rugby World Cup Kearney was selected but was injured for the first game against the United States; however, he played in all the other matches which took Ireland through to the quarter-finals, in which they were knocked out by Wales, 22–10.

Kearney was selected in the Ireland squad for the 2012 Six Nations Championship and named in the starting team to play Wales in the opening match.

Kearney was also in the first Irish rugby team in 39 years to beat Australia on Australian soil, in the 2018 summer series.