James Cornell Biddle, Jr., was born on October 3, 1835, in Philadelphia, Pennsylvania, to James C. Biddle and Sarah Kepple. His father was a lawyer who died in 1838. Biddle grew up and attended school in Philadelphia before beginning work as a civil engineer. He enlisted in the Union army on April 25, 1861, and mustered in as a private in Company A of the 17th Pennsylvania Infantry. He mustered out on August 2, 1861, at the end of his three-month term of enlistment. He returned to the army soon afterward, receiving a commission as a 1st lieutenant in Company C of the 27th Pennsylvania Infantry on November 1, 1861. He eventually earned promotions to captain and then major, and he served on the staff of General George Gordon Meade. After the war, he was brevetted colonel for “gallant and meritorious services during the recent operations resulting in the fall of Richmond and the surrender of the insurgent army under General Robert E. Lee.”
Biddle married Gertrude Meredith in Philadelphia on December 27, 1862, and they had at least two children: Catherine, born around 1865; and Sarah, born around 1866. Biddle returned to Philadelphia after the war and worked as a “drug merchant.” By 1870, he owned $12,000 of real estate and $700 of personal property, and he employed at least three Irish domestic servants. A decade later, he was working as a “manufacturer of cotton.” He died in Philadelphia on November 2, 1898.