Junius N. Spratley was born around 1838 in Virginia to John and Sarah Spratley. His parents probably died when he was a child, and by 1850, he was living in the household of Mary C. Lamb in Southwark, Virginia. By 1860, he was working as a clerk in Petersburg, Virginia.
He enlisted in the Confederate army on March 26, 1862, and he mustered in as a private in Company G of the 13th Virginia Cavalry. The regiment took part in the Battle of Fredericksburg, the Battle of Chancellorsville, the Battle of Brandy Station, the Battle of Gettysburg, the Overland Campaign, and the siege of Petersburg. He fell ill in October 1864, and surgeons sent him to a hospital to recover. It is unclear if he rejoined the regiment.
He settled in Leavenworth, Kansas, after the war, and he earned a living as a miller. By 1870, he owned $8,000 of real estate and $200 of personal property. He died in the fall of 1883.