Nathaniel H. Bostwick was born on June 20, 1828, in East Bloomfield, New York. He eventually moved to Medina, Ohio, and he married a woman named Martha. He worked as a lawyer, and by 1860, they owned $800 of real estate and $1,500 of personal property.
He enlisted in the Union army on May 15, 1864, and he mustered in as a private in Company E of the 166th Ohio Infantry. Army officials assigned the regiment to garrison duty as part of the defenses of Washington, D.C. He eventually earned a promotion to sergeant major, and he mustered out on September 9, 1864.
He returned to Medina after leaving the army and resumed his work as a lawyer. His wife probably died in the early 1860s, and he married a woman named Frances soon afterward. They had at least three children: Harry, born around 1864; Frederick, born around 1868; and Emily, born on November 15, 1870. By 1870, he owned $3,500 of real estate and $500 of personal property. He applied for a federal pension in May 1891 and eventually received one. He died of heart disease in Medina on February 4, 1896.