Edgar's father, Matthew Wilson, joined the Union Army in 1862, and one account suggests he was wounded and captured at White Sulphur Springs, West Virginia, in 1863. He was promoted to captain while in prison, and he died a prisoner at Libby Prison in 1864. Another account is that Matthew Wilson was captured in the Battle of Turner's Gap in 1862, was taken to Libby Prison then moved to Charleston where he died of insufficient rations, inadequate clothing, and the deprivations of confinement 10 months after capture. Edgar Wilson would have been either two or three years old when his father died.