Born in approximately 1838 in Ireland, John Hefferman eventually emigrated to the United States. He enlisted in the 13th New York HG on January 7, 1864 in Buffalo, New York. He received his discharge orders from the War Department on June 28, 1865 in Norfolk, Virginia. He returned to Buffalo and eventually married Alice Hefferman. Their son, Thomas John, was born in Buffalo in 1878.
At some point, the Heffermans moved west to Cleveland. It is in Cleveland that his wife, Alice, passed away in 1907. She is buried in the same cemetery as their son. Widowed, John entered into Battle Mountain Sanitarium at 73 years of age, in January of 1911 with articular rheumatism, constipation, hemorrhoids, and varicose veins. He described himself as a five-foot-seven, gray-eyed, literate, Catholic laborer. He passed away on May 8, 1913 from mitral insufficiency and is interred at Hot Springs National Cemetery.