In 1979 Larkin won his ninth Leinster medal as Kilkenny defeated Wexford by 2–21 to 2–17. "The Cats" later faced surprise finalists Galway in the All-Ireland decider on 2 September 1979. In one of the worst All-Ireland finals of the decade, Tipperary-born Galway goalkeeper Séamus Shinnors had an absolute nightmare of a game. A 70-yards free by Liam "Chunky" O'Brien after just four minutes dipped, hit off Shinnors and ended up in the Galway net. Galway fought back and went two points up twelve minutes into the second half, however, they failed to score for the rest of the game. Four minutes before the end of the game another long-range free for Kilkenny ended up in the net behind Shinnors. It was a score which summed up the day for Galway as Kilkenny went on to win by 2–12 to 1–8. Larkin, the oldest man on the field of play, collected his fifth and final All-Ireland medal.