O'Brien first played Gaelic football and hurling in the Lough Leagues, before later lining out as a schoolboy with Sullivan's Quay CBS. He had his first success at club level when he won a Cork MFC title with St. Finbarr's in 1968. O'Brien was still in his teens when he lined out with the intermediate team before making his senior debut as a dual player.
O'Brien has his first senior successes as a hurler when St. Finbarr's claimed the Cork, Munster and All-Ireland titles during the 1974–75 season.[1] Over the course of the following decade he enjoyed many more successes, including a second All-Ireland club hurling medal in 1978 and All-Ireland club football victories in 1980 and 1981.[2] O'Brien became only the second player since John Lyons to captain his club to hurling football honours.[3] His career effectively ended after breaking his leg in a club game in 1983.
In retirement from playing, O'Brien became active as coach and selector with various St. Finbarr's teams. He was part of the management team when the club won their third All-Ireland club football title in 1987. O'Brien also spent nearly 25 years as a member of the club's hurling committee.[8]
Death
O'Brien died on 2 March 2023, at the age of 71.[9]