Kennefick joined the Glen Rovers club at a young age and played in all levels at juvenile and underage levels. It was the club with whom his grandfather, Christy Ring, won a record 14 championship titles.[2] Kennefick had his first championship success at minor level when Glen Rovers secured the 2017 Premier 1 Championship title after a 0-19 to 1-11 defeat of Midleton in the final.[3] He was subsequently drafted onto the Glen Rovers senior team and made his championship debut on 28 April 2018 when he scored 1-03 in a first round defeat of Ballymartle.[4] Kennefick lined out in three successive county finals over the following three seasons, experiencing defeats to Imokilly in 2019, Blackrock in 2020 and Midleton in 2021.[5][6][7]
Cork
Under-21 and under-20
Kennefick never played at minor level for Cork, but was drafted onto the under-21 team in 2018. He was a member of the extended training panel when Cork secured the Munster Championship title after 2-23 to 1-13 defeat of Tipperary in the final.[8] He was again eligible for the now renamed under-20 grade the following year and made his first appearance at right wing-forward in a 1-20 to 0-16 first-round defeat of Limerick.[9] On 24 August 2019, Kennefick was a late addition to the Cork starting fifteen that suffered a 5-17 to 1-18 defeat by Tipperary in the All-Ireland final.[10]
Senior
Kennefick made his first appearance for Cork at senior level when he was selected on the team at right wing-forward for the annual Canon O'Brien Cup game against University College Cork in January 2019. He scored four points from play in the 1-24 to 1-23 victory but was not included on the Cork panel for the rest of the season.[11]
In May 2021, Kennefick received his first competitive call-up at senior level when he was named amongst the substitutes for Cork's National League game against Westmeath.