Listed at 6 ft 0 in (1.83 m), 185 pounds (84 kg), Heflin was born in Fredericksburg, Virginia.

Heflin's pro career extended from 1939 to 1952, although he missed the 1943–44 seasons while serving in the United States Navy during World War II.

[1] He returned to baseball during the final year of the war, winning three of five decisions for the top-level Louisville Colonels before the Red Sox recalled him.

He threw two complete-game shutouts: a four-hitter August 10 against the eventual world champion Detroit Tigers and a six-hitter September 20 against the last-place Philadelphia Athletics.

[2] In 1946, the first postwar year, Heflin appeared in five games for the Red Sox between April 21 and June 12, including one start, and lost his only decision.