On July 17, 1921, in Bluefield, West Virginia, Boykin and Willa (née Maynard) Stone welcomed Marcenia Lyle Stone into the world. In 1931, the Stone family moved to live in the Rondo neighborhood of St. Paul, Minnesota. As a child and teen, Stone, against her parents wishes, primarily engaged in activities and sports, including baseball, with the local boys. Her engagement was to the extent that she was called “Toni Tomboy”. During this time, Stone played with the HiLex girls’ softball team and became the first girl to play on the St. Peter Claver Catholic Church boys’ baseball team, encouraged by her mentor and priest, Father Charles Keith. Stone also played on the St. Paul Men’s Meat Packing League baseball team.
In 1936, she convinced Gabby Street to allow her to try out for his baseball school. Street, a former catcher with the St. Louis Cardinals, also managed the Cardinals in the 1930s as well as a minor league baseball team, the St. Paul Saints. Impressed with her ability, Street overlooked her race and gender and allowed her admittance. The following year, Stone, at the age of sixteen years old, joined the barnstorming, semi-professional team, the Twin City Colored Giants. Having started out shagging baseballs for the team, Stone pitched for the Colored Giants as they traveled throughout the Midwest and Canada. In the biography of Stone featured in Minnesotans in Baseball, edited by Stew Thornley, journalist Jimmy Lee, in the July 30, 1937 Minneapolis Spokesman, said, “The team has the distinction of having a girl pitcher on its roster. No other team in the Northwest can boast the same. Miss Marcenia Stone, 16-year-old girl athlete, has been doing much to amuse the fans with her great catcher [sic] and wonder hitting power.”