Edwin W. McNitt was born on September 22, 1838, in Seneca County, Ohio, to James McNitt and Matilda Wakefield. The family moved to Michigan shortly after he was born and settled in the town of Ovid. His father died in the early 1850s. By 1860, he was working as a farmer in Porter, Michigan. He married Angelia Crandall around 1860, and they had at least two children: Chester, born around 1861; and Albertus, born around 1863.
McNitt enlisted in the Union army on February 26, 1864, and he mustered in as a private in Company F of the 12th Michigan Infantry three days later. He mustered out on February 15, 1866. His wife died of tuberculosis shortly after the war, and he married Julia Underhill on June 15, 1869. They had at least two children: Edson, born around 1872; and Gertrude, born around 1875. They settled in Bristol, Indiana, and McNitt worked as a carpenter. They moved to Algansee, Michigan, in the 1870s.
He applied for a federal pension in December 1889, complaining of “neuralgia.” His wife died in 1908, and by 1910, he was living in his son Edson’s household in Algansee. He died in Reading, Michigan, on September 15, 1912.