James Bernard Mahady (April 22, 1901 – August 9, 1936) was a professional baseball second baseman and pitcher, whose career spanned seven seasons, which included one in Major League Baseball (MLB) with the New York Giants (1921). While in the majors, Mahady played in one game, and had no plate appearances. The majority of his career was spent in the minor leagues as a pitcher. He batted and threw right-handed. In the minors, he compiled a 69–50 record. During his playing career, Mahady stood at 5 feet 11 inches (180 cm) and weighed 170 pounds (77 kg).