Joseph Mackey Brown graduated from Oglethorpe University and studied law at Harvard, passing the bar in 1873. Due to failing eyesight, he transitioned from law to a career in railroads, eventually becoming a traffic manager for the Western and Atlantic Railroad. Brown held various leadership roles, including a position on the Georgia State Railroad Commission, and authored books on Georgia history and fiction. His career also included financial sector involvement as a director and vice president of a national bank and ownership of a mill.

Joseph Mackey Brown's political identity is marked by a blend of traditional Southern values and an inclination towards populist rhetoric. His involvement in the lynching of Leo Frank reveals a willingness to engage in extra-legal actions to achieve what he sees as justice, while his career in railroad regulation indicates a focus on regional economic interests. Brown's approach to governance appears to balance a rigid adherence to certain moral imperatives with a pragmatic engagement in economic issues.