Born in Madill, Oklahoma, he batted and threw right-handed and was listed as 6 feet 2 inches (1.88 m) tall and 190 pounds (86 kg).

The following season, in 1945, Muncrief led all Junior Circuit hurlers in winning percentage, posting a .765 mark based on his 13–4 record.

Two years later, on September 30, 1937, Muncrief made his MLB debut starting for the Browns against the Detroit Tigers, allowing two runs (one earned) in two innings pitched.

In 1941—baseball's last pre-World War II season—Muncrief, still a rookie at age 25, began the year in the Brownie bullpen until getting four starting assignments in late May and early June.

Pitted against their National League rivals, the Cardinals, in the all-St. Louis 1944 World Series, Muncrief was relegated to a relief role in his two appearances, each time replacing starter Nels Potter.

He quelled a Cardinal rally and threw two more shutout frames, but the NL champions had already forged an insurmountable 3–1 lead en route to the world championship.

He finished 22nd in voting for the 1945 American League Most Valuable Player Award for his 13–4 won–lost record, ten complete games and 2.72 ERA.

Pitching infrequently as both a starter and reliever during the campaign's first three months, he lowered his earned run average to 1.58 on June 26 after a three-hit shutout of the Washington Senators improved his won–lost mark to 5–1.

He then spent all of 1950 in the Triple-A Pacific Coast League, where he won 15 games and earned his final MLB opportunity as a Rule 5 selection of the New York Yankees.