Duncan Green Campbell was born around 1835 in Alabama to John A. Campbell and Anna Goldthwaite. His father was a lawyer and Supreme Court Justice who owned $55,000 of real estate and $70,000 of personal property by 1860. He grew up and attended school in Mobile, Alabama, and he studied engineering in Austria sometime before the Civil War.
He sided with the Confederacy during the war, and he served as a lieutenant in the Confederate Engineer Corps. He was promoted to captain in March 1864, and he served until April 1865. He settled in New Orleans, Louisiana, after the war. He married Ella Calvert, whose father
Charles B. Calvert was a UVA alumnus who remained loyal to the Union. The couple had at least four children: Charlotte, born around 1863; Ella, born around 1864; John, born around 1866; and Anna, born around 1868. He earned a living as a lawyer and a farmer, and by 1870, he owned $2,000 of personal property. The family moved to Vansville, Maryland, in the 1870s. He died in Washington, D.C., on March 13, 1888.