Duke received a private education suitable to his class, then following his father's death, was sent to Lexington, Virginia, for higher studies.

In 1858 Duke won his first election, and became the Commonwealth's Attorney for Albemarle County, Virginia, where he would be re-elected even during the American Civil War and served until 1869.

In November, 1859, following the unsuccessful raid on Harper's Ferry, and Brown's trial, Duke organized the Albemarle Rifles at Charlottesville.

In late September 1864, they were sent to man trenches at Fort Harrison, then retreated to new lines at Chaffin's Bluff before returning to Richmond to guard Libby Prison.

[7] After being released from prison in July, 1865, Duke returned to Charlottesville and helped organize a local citizen group to prevent "black domination.

In 1870, he won a contested election, running as a Conservative against fellow Albemarle county planter and lawyer Alexander Rives, a Republican who courteously and without his normal charge secured a pardon for Duke in order to remove any taint of civil disability.

In his retirement, about 1899, Duke began writing his reminiscences of Charlottesville and Albemarle County for his five children and eventually grandchildren.

Over the next two decades (ending months before his death), they eventually reached five bound volumes, and are held by the University of Virginia library.