In 1975 a new-look Kerry team was formed under the management of former player Mick O'Dwyer. It was the beginning of a glorious era for Kerry football and Kennelly played a key role in orchestrating much of the success for the team that would come to be regarded as the greatest of all-time. That year he won his first senior Munster title, dethroning Cork as provincial champions in the process. Kennelly later lined out in his first senior All-Ireland final. Reigning champions Dublin provided the opposition and were installed as the favourites over the youngest Kerry team of all-time. On a rain-soaked day John Egan and substitute Ger O'Driscoll scored two goals and 'the Dubs' were ambushed by 2–12 to 0–11. It was Ó Kennelly's first All-Ireland winners' medal at senior level.