Born January 17, 1874 in Sandwich, Massachusetts, on Cape Cod, Burgess was the son of Caroline F. Haywood and Thornton W. Burgess Sr., a direct descendant of Thomas Burgess, one of the first Sandwich settlers in 1637. Thornton, Sr., died the same year his son was born, and the young Thornton, Jr. was brought up by his mother in Sandwich. They lived in humble circumstances. As a youth, he worked tending cows, picking trailing arbutus (mayflowers) or berries, shipping water lilies from local ponds, selling candy, and trapping muskrats. William C. Chipman, one of his employers, lived on Discovery Hill Road, a wildlife habitat of woodland and wetland. This habitat became the setting of many stories in which Burgess refers to Smiling Pool and the Old Briar Patch.