[3][4] His parents were Julius Adolphus, Sr., (1798–1840) and Harriet (née Sanford) De Lagnel; his father was a United States Military Academy graduate (class of 1821) who was an ordnance officer and served in Florida during the Second Seminole Wars.

[3] In June 1861, he was assigned as chief of artillery to Brigadier General Robert S. Garnett, commander of the Army of the Northwest.

Garnett had been sent to reorganize the Confederate force in the western counties of Virginia after their rout at the Battle of Philippi and to hold the area for the Confederacy.

[3] After De Lagnel used the sole artillery piece to fight by himself for a period of time, he was wounded and hid in a thicket in an effort to escape from the Union troops.

[3] De Lagnel was appointed and confirmed as a Confederate brigadier general to rank from April 12, 1862, but on July 31, 1862, he declined the commission.

[3][4] He died on June 3, 1912, at Washington, D.C.[3][4] Julius Adolph De Lagnel was buried in the cemetery of St. Paul's Episcopal Church, Alexandria, Virginia.