Club
In his youth Fennelly quickly became a member of the newly formed Ballyhale Shamrocks club,a club which is father helped to found. He had much success with the club,beginning by winning several minor and under-21 county titles with the club. In 1978 Fennelly was a key member of the senior team when Ballyhale won their first county title. This was later converted into a Leinster club title,however,Ballyhale were narrowly beaten by Blackrock in the All-Ireland final.
Fennelly added two further county medals to his collection in 1979 and 1980. In the latter year he won a second Leinster title before finally winning his first All-Ireland club title at the beginning of 1981. In 1982 and 1983 he won another brace of county championship medals. The 1983 win was once again converted into a Leinster title as well as a second All-Ireland club title at the start of 1984. Fennelly brought his county championship tally up to eight with wins in 1985,1988 and 1989. In 1989 he also won his fourth Leinster club medal before converting this into his third All-Ireland club title. On the occasion of the final all seven Fennelly brothers lined out for Ballyhale,a record which will probably never be beaten. Fennelly won his ninth county medal with Ballyhale in 1991.
Inter-county
Fennelly’s hurling skills were quickly noted and he joined the Kilkenny minor hurling panel in the early 1970s. It was a glorious era for the county’s minor hurling team as they dominated the minor provincial championship for the entire decade. He won a Leinster title in this grade in 1971,however,Kilkenny were beaten in the All-Ireland final by Cork. Fennelly won a second provincial title in 1972,however,‘the Cats’gained revenge on Cork in the championship decider and Fennelly collected an All-Ireland Minor Hurling Championship medal. He quickly joined the Kilkenny under-21 team where he won back-to-back Leinster and All-Ireland titles in 1974 and 1975. Fennelly won a third provincial under-21 title in 1976,however,Kilkenny were defeated by Cork in the subsequent All-Ireland final.
Fennelly subsequently joined the Kilkenny senior hurling panel,however,he found it difficult to find a regular spot on the team. He won a Leinster title in 1979 before later coming on as a substitute to claim a senior All-Ireland medal. Fennelly won several other Leinster and All-Ireland titles throughout the 1980s but as a substitute. He finally took over as goalkeeper from Noel Skehan and won back-to-back Leinster titles on the field of play in 1986 and 1987. In the latter year his side were defeated by Galway in the All-Ireland final. In spite of this Fennelly won a National Hurling League medal in 1986. Four years later in 1990 he won a second National League medal and he retired from inter-county hurling shortly afterwards.
