Stephen Fowler Kennedy was born around 1840 in Pennsylvania, and he grew up in Tioga County, Pennsylvania.
He enlisted in the Union army on September 21, 1861, and he mustered in as a private in Company I of the 45th Pennsylvania Infantry later that day. The regiment took part in the Battle of Antietam, the Battle of Fredericksburg, the siege of Vicksburg, the siege of Jackson, the Knoxville campaign, the Overland Campaign, the siege of Petersburg, and the Appomattox campaign. A comrade later described him as “fearless in battle, devoted to duty, and a generous and genial companion.” He mustered out on July 17, 1865.
Kennedy returned to Tioga County after the war, and he married a woman named Laura in December 1866. They had at least two children: Ada, born around 1867; and Burton, born around 1871. They lived in Wellsboro, Pennsylvania, and Kennedy worked as a farmer. By 1870, he owned $1,000 of real estate. He applied for a federal pension in June 1880 and eventually secured one. His wife died on December 20, 1894, and he passed away on April 21, 1900.