Moulder batted and threw right-handed, stood 6 feet (1.8 m) tall and weighed 180 pounds (82 kg).

Moulder began his pro career in the Brooklyn organization in the Class D Nebraska State League in 1937.

He then performed World War II service in the United States Army Air Forces, and missed the 1943–1945 seasons.

[2] He spent the balance of 1946 with the Triple-A Montreal Royals, who won the International League and Junior World Series championships led by Jackie Robinson in his historic first season in previously-all-white Organized Baseball.

Moulder then spent two full seasons in the American League, working in 32 games for the St. Louis Browns in 1947 and 33 contests for the Chicago White Sox in 1948.