He played for the Newport Buffaloes high school team. Signed as an amateur free agent by the Pittsburgh Pirates in 1940, Cox made his MLB debut with the Pirates on September 20, 1941, playing in ten games at shortstop that season[1] before serving in the military during World War II.
In the 1953 World Series, Cox had a two-run double in Game 2 and a three-run homer in Game 5 against the New York Yankees. He batted .304 for the Series and led Brooklyn in runs batted in with six.
Cox was acquired along with Preacher Roe by the Baltimore Orioles from the Dodgers on December 14, 1954 for a pair of minor-leaguers, infielder Harry Schwegman and right-handed pitcher John Jancse, and $60,000.[2] He was an infield starter (principally at third base) and leadoff hitter for the Orioles for the first half of 1955. He was traded along with Gene Woodling from the Orioles to the Cleveland Indians for Dave Pope, Wally Westlake and cash before the trade deadline on June 15, 1955.[3] He would not report to his new team. Even after a meeting with Indians' manager Al López, Cox resolved to retire and did so on June 17.`