Ulster described him as a "talismanic player ... known for his sniping runs, kicking success, and ability to dictate games" whose "performances for the province had seen him consistently rank among the top points-scorers in the PRO14, now United Rugby Championship, competition.

[2] Cooney made his senior debut for Leinster on 2 September 2011, when he started against Ospreys in Swansea during the opening game of the 2011–12 Pro12.

[6] Most of his appearances came while Leinster's front-line players were away at the 2011 World Cup, though he also scored his first try for the team later in the season in a win over Benetton Treviso.

[8] He did not feature as regularly for Leinster in the 2013–14 season as he had the year before, finding himself behind internationals Eoin Reddan and Isaac Boss on the depth chart.

While Roux would return to Leinster in January 2015, Cooney agreed a deal to play with Connacht until the end of the season.

[9] After the IRFU prevented South African international Ruan Pienaar from extending his contract, Ulster signed Cooney from Connacht as his replacement ahead of the 2017–18 season.

[11] He was named at scrum-half in the Pro14 Dream Team for the season,[12] having topped the league in points scored, try assists, penalties and passes, and come second in clean breaks.

[29] In December 2022 he won the inaugural URC Difference Maker award for his volunteer work with Belfast Central Mission's befriending service.