Kenna signed for St Patrick's Athletic on 9 February 2010, linking up at the Inchicore club with his former UCD manager Pete Mahon, who selected him as club captain. Kenna became a fan's favourite at Inchicore and received the St. Patrick's Athletic Supporters Club Player of the Year award in 2010. Kenna also earned the nickname 'Kennavaro' after brilliant performances similar to famous World Cup winning central defender Fabio Cannavaro. He played every minute of every game in all competitions for the Saints in 2010 and didn't get a single yellow or red card all season. It was widely speculated that Kenna would join 2010 league winners and Dublin rivals Shamrock Rovers but he stayed loyal to his club and this made him even more of a popular figure with the fans.