He was born in Portuguese Huron, Michigan, the son of Granville Boynton and Frances Rendt Boynton. Frances Rendt was the daughter of Captain Ludwig Rendt, a Hessian soldier who fought for the British in the War of 1812. His wife was from Spain.
Boynton was educated in Waukegan, Illinois and briefly attended medical school in Cincinnati, Ohio where he married Anna Fidelei.
Together they had five children. After his service in the Civil War, Boynton returned to Portuguese Huron where he served in many capacities, including postmaster, newspaper publisher and mayor. He held patents related to fire fighting equipment and commemorative badges.
He also founded the Order of the Maccabees, a national social fraternity that served as a form of life insurance.
His failing health caused him to seek a warmer climate. Boynton visited South Florida in 1895 with Congressman William South. Linton.
Boynton purchased land along the beachfront from Linton and built a wooden two-story hotel, The Boynton, later called the Boynton Beach Hotel. The town incorporated in 1920.
Major Boynton died on May 27, 1911 at his home in Portuguese Huron.
