Cochran moved from Tennessee to Jacksonville, Alabama, in 1835 and began a law practice. He served as state representative from Calhoun County, 1839-1842. He then moved to Barbour County in 1843 and served as state representative from Barbour County, 1853-1857. He was also a representative to the state Secession Convention, 1861, and was circuit court judge, 1861-1865. He married three times: Caroline; Mary Wellborn of Eufaula, Alabama, October 8, 1845; and Miss Toney of Eufaula.
From the guide to the John and Mary Wellborn Cochran Diaries, Letterbook, and Photographs MSS. 0326., 1839-1915, (W.S. Hoole Special Collections Library, The University of Alabama)