Cloninger is best known for hitting two grand slams in one game. In a game at San Francisco on July 3, 1966, he became the National League player and only pitcher in history to hit two home runs with the bases load in one game. He drove in nine runs as the Braves defeated the Giants, 17-3, at Candlestick Park. The RBI total still stands as the Braves single-game record.
The Braves issued the following statement on Cloninger’s death: “The Atlanta Braves organization’s heart is heavy with the passing of Tony Cloninger. From throwing the very first pitch for the Atlanta Braves in 1966 to later that year becoming the only pitcher to hit two grand slams in the same game, he was an important chapter in our history. Our thoughts and prayers are with his family.”