Boynton was born in Whitney Point, New York on August 12, 1877 to George G. and Eliza Ann (née Boatman) Boynton where he also grew up. He attended Cornell University from 1897 to 1900, graduating with a degree in law. While at Cornell he played on the varsity football team as well as the varsity track & field team. Boynton lettered in track & field in 1899 and 1900 primarily competing in the hammer throw. He had the seventh best throw in the nation in 1900 with a distance of 44.9m in a meet in Philadelphia, Pennsylvania.
After he finished coaching at Kansas in 1900 he returned to New York state where Boynton married Grace G. Stanton on September 6, 1902, just 2 months before he would head off to coach at Sewanee. He later worked as a lawyer first in New York state starting in 1905 even though he had already passed the New York Bar exam in 1900, then in Florida for 4 years starting in 1926 and then in North Carolina starting in 1929. Boynton died in Cabarrus County, North Carolina at his home in 1937. He was buried back in his hometown of Whitney Point, New York in Riverside Cemetery.