John was born on the 21st of June 1874, in Lanarkshire, Scotland, and he came to the United States at a young age (information varies from 1879 to 1888). He grew up in Brooklyn, New York, with his four sisters and he enlisted in the US Navy. It was his actions as a Fireman Second Class during the Spanish-American War that would earn him the Medal of Honor. The citation reads:

On board the U.S.S. Marblehead during the operation of cutting the cable leading from Cienfuegos, Cuba, 11 May 1898. Facing the heavy fire of the enemy, Maxwell displayed extraordinary bravery and coolness throughout this action.

John received the Medal of Honor on the 7th of July 1899, and he was married twice, first to Ella Pine and second to Augusta Thurman, which whom he had two daughters. Not much else is recorded about his life and service: John Maxwell died on the 13th of November 1931, at the age of 57 and he is buried with his wife in the Westbury Friends Cemetery in Westbury, New York.