John Roberts Tunis was born on December 7, 1889, in Boston, Massachusetts, where his father served as a Unitarian parson and his mother worked as a schoolteacher. His father died when Tunis was six, and the family moved to New York City, where his mother, Caroline, raised Tunis and his younger brother while she taught at a private academy for girls. Tunis grew up in a household that placed a very high value on all of the elements of a traditional classical education. In addition to the standard works of literature his mother recommended, Tunis and his younger brother read all of G. A. Henry's books to each other.

The family moved back to the Boston area in 1899, and in 1901 Caroline Tunis's father took the brothers to their first baseball game, insisting that the sport was a part of American heritage.

In accordance with family expectations...