Mary Pratt pitched in the All-American Girls Professional Baseball League from 1943 to 1947.
Her family moved to Quincy, MA when she was 12. She was an avid sports fan and player in her youth and had to play against boys, given there were few opportunities for women to play organized sports at the time. She played baseball, softball and basketball. She studied physical education at Boston University, graduating in 1940, then began a career as a teacher in local schools.
When the AAGPBL was formed in 1943, Mary attended a tryout to recruit players held in Rockford, IL. She joined the Rockford Peaches, for which she went 5-11. In 1944, after a few games with Rockford, she was re-assigned to the Kenosha Comets when that team lost a couple of players to injuries. Managed by former major league player Marty McManus, she won 21 games that season and pitched a no-hitter against Minneapolis. She retired from teaching at that point to concentrate on her baseball career, and played one more season for Kenosha in 1945, and then two for Rockford.
She then returned to teaching in the Boston area, including some time as an associate professor at Salem State College in the late 1960s. She later served on the board of the AAGPBL Players Association.