Joseph Robert Davis was born to Isaac Williams Davis (October 1792-1834), older brother of Jefferson Davis (June 3, 1808-December 6, 1889), and Susannah Gartley (March 18, 1794-March 6, 1874) in Woodville, Wilkinson County, Mississippi on January 12, 1825. After briefly staying at eldest brother Joseph Emory Davis' (December 10, 1784-September 18, 1870) "Hurricane" plantation in Warren County, Mississippi, Isaac relocated his family to Madison County, Mississippi about 1830. Joseph Robert was educated in Kentucky before graduating from Miami University in Oxford, Butler County, Ohio. He returned to Madison County, Mississippi, married Frances H. Peyton in 1848, began the practice of law in 1851, and also became actively involved in farming.

     He was elected to the Mississippi legislature in 1860, and following the secession of his state, he became Captain of the "Madison Rifles", which was later designated Company I of (Old) 10^th Mississippi Infantry. He was elected Lieutenant Colonel of the Regiment on April 12, 1861, and was stationed at Fort Barrancas and Fort McRee, near Pensacola, Escambia County, Florida. His uncle, President Jefferson Davis (June 3, 1808-December 6, 1889), requested Joseph Robert to join him on his personal staff that summer, and he was appointed Aide de Camp with the rank of Colonel on August 31, 1861. After a year of assessing military matters and making reports, he sought more active military service. He was promoted to Brigadier General on September 26, 1862, and was placed in command of a brigade on November 8, 1862. His brigade, comprised of 2^nd, 11^th, 26^th, and 42^nd Mississippi Infantry, 1^st Confederate Battalion, and Madison Light Artillery, was engaged for the balance of the war with Army of Northern Virginia, and earned great respect for its fighting during the Battle of Gettysburg (July 1-3, 1863).

     After his parole at Appomattox Court House, Appomattox County, Virginia (April 9-12, 1865), he returned to the practice of law. He divorced in 1878, and married Margaret Cary Green (1850-January 15, 1939) on March 18, 1879. He spent his latter days at his uncle's home, "Beauvoir", in Biloxi, Harrison County, Mississippi, where he died on September 15, 1896. Joseph Robert Davis is buried in Biloxi Cemetery.