Miles L. Smith was born around 1838 in Connecticut to Lewis and Abigail Smith. His father was a farmer who owned $3,000 of real estate and $200 of personal property. He grew up and attended school in Milford, Connecticut, and by the early 1860s, he was working as a joiner in New Haven, Connecticut. He married a woman named Catherine around 1861, and their daughter Grace was born around 1866.
He enlisted in the Union army on September 10, 1861, and he mustered in as a private in Company K of the 10th Connecticut Infantry on October 29. The regiment took part in the siege of Charleston and the siege of Petersburg. He was promoted to corporal in July 1862 and to sergeant in November 1864. He mustered out on August 25, 1865.
He returned to New Haven after the war, and he worked as a carpenter. By 1870, he owned $500 of personal property. He applied for a federal pension in September 1890 and eventually received one. By 1900, he was apparently living separately from his wife. He attended regimental reunions in 1910, 1903, 1906, and 1908. By 1910, he was living at Fitch’s Home for Soldiers and Orphans in Darien, Connecticut. He died on April 18, 1911.