Arthur Caswell Paker was born on April 5, 1881 in the Cattaraugus Reservation of the Seneca Nation of New York in western New York into a Seneca Indian family prominent on the Cattaraugus Reservation at Iroquois, New York. He was the son of Frederick Ely Parker, a railroad accountant of part Seneca descent, and Geneva H. Griswold, who was of Scottish and English ancestry. His grandfather, Nicholson H. Parker, with whose family Parker spent much of his early life, was clerk of the Seneca Nation, United States interpreter, census agent, marshal, and a successful farmer. A great-uncle, Brigadier General Ely S. Parker, was military secretary to General Ulysses S. Grant, who appointed him first Commissioner of Indian Affairs after Grant became president. Parker's early years on the reservation developed in him an abiding interest in natural history and in the history and traditions of the Iroquois. His intellectual bent was stimulated by the scholarly concerns of his grandfather.