James Seddon was born in Falmouth, Virginia, on 13th July, 1815. After graduating from the University of Virginia in 1835 he was admitted to the bar and practiced law in Richmond.
A member of the Democratic Party, Seddon was elected to Congress and served for two spells (4th March, 1845 - 3rd March, 1847 and 4th March, 1849 to 3rd March, 1851).
Seddon was a member of the peace convention held in Washington in 1861 that attempted to devise a means of preventing the American Civil War. Seddon also attended the Provisional Confederate Congress in 1861. President Jefferson Davis appointed Seddon as his Secretary of War in November, 1862 and held the position until January, 1865.
When the Union Army arrived in Andersonville in May, 1865, photographs of the prisoners were taken and the following month they appeared in Harper's Weekly. The photographs caused considerable anger and calls were made for the people responsible to be punished for these crimes. It was eventually decided to charge Seddon, General Robert Lee, and several other Confederate generals and politicians with "conspiring to injure the health and destroy the lives of United States soldiers held as prisoners by the Confederate States". In August, 1865, President Andrew Johnson ordered that the charges against Seddon and the Confederate generals and politicians should be dropped.
James Seddon died in Goochland County, on 19th August, 1880.