After his playing career, he coached with the Yankees for 10 years, during which period they won six pennants and two World Series, including the great 1927 Yankees team. And, on September 30, 1934, several weeks shy of his 59th birthday, O'Leary was brought out of retirement by the St. Louis Browns. In a pinch-hitting appearance, he singled and subsequently scored, becoming both the oldest Major League Baseball player to collect a hit and score a run.