Pickle was born on his family's homestead farm in
Knox County, Tennessee, one of eleven children of Jonathan and Margaret (Underwood) Pickle. His father was a prosperous farmer and businessman in the county, and Pickle was of Irish and German descent. He spent part of his youth in Jefferson County, and received his early education in the common schools of Knox County and at Sweetwater, Tennessee. In 1859, he attended the East Tennessee University (now the
University of Tennessee). Shortly thereafter, the
American Civil War broke out, and early in 1863, at age seventeen, Pickle enlisted as a private in Company E, Second Tennessee Mounted Infantry (also referred to as Second Tennessee Cavalry), under Colonel
Henry Marshall Ashby. He was captured by Federal forces at
Lancaster, Kentucky in July 1863, during
Scott's raid and spent about eight months at
Camp Chase and nearly twelve months at
Fort Delaware, reportedly refusing an offer of release on condition of taking the oath of allegiance. He remained imprisoned until paroled near the close of the war. After the war Pickle attended
Princeton University in New Jersey for about two years, but left before graduation due to financial difficulties. From 1868 to 1870, he
read law under Senator
Daniel W. Voorhees at Terre Haute, Indiana, gaining
admission to the bar in Tennessee in 1870. ==Legal career==