A left-hander and native of Alexandria, Virginia, he appeared in 31 games over parts of three seasons (1942, 1946–1947) with the Washington Senators of Major League Baseball.

That same year, he debuted with the Senators in May, working in eight games (six in relief, losing his only decision and posting a poor 9.00 ERA; he was credited with two saves.

[1] In 1946, the first full postwar season, Kennedy spent the entire year on the Senators' MLB roster, working in 21 games and gaining his only big-league victory, with three more saves.

During his MLB tenure, he compiled a 1–3 won–lost record, five saves, one complete game in four starting assignments, and a 6.79 earned run average.

His victory came on June 3 at Griffith Stadium when he threw 4⅔ shutout innings in relief of Dutch Leonard against the Detroit Tigers.