James Fowler Rusling was born on April 14, 1834 in the town of Washington in Warren County, New Jersey, the fifth of the seven children born to Geishom and Eliza Hankinson Rusling. He was prepared at the Pennington School and entered Dickinson College, in Carlisle, Pennsylvania in 1852, joining the class of 1854. While there he studied the natural sciences and was a member of the Union Philosophical Society. He graduated with his class and immediately took up a teaching post at the Dickinson Williamsport Seminary, where he taught until 1857. He was admitted that year to the Pennsylvania bar and to the New Jersey bar in 1859 when he set up practice in Trenton.
On August 24, 1861, he became a first lieutenant and the regimental quarter-master of the 5th New Jersey Volunteer Infantry. By October 1862, he was a captain and quartermaster of the 2nd Division of III Corps and in May 1863, he was named as a lieutenant colonel of Volunteers and 3rd Corps Quartermaster. At the end of the war he was the Inspector of the Quarter Master Department of the United States Army and received a brevet promotion in February 1866 as Brigadier General of Volunteers before returning to private practice in September 1867. His extensive service in all of the campaigns of the Army of the Potomac between 1861 and 1863, together with his activities in the Army of the Cumberland for the remainder of the war, are detailed in his 1899 book, Men and Things I Saw in Civil War Days. Rusling was an observant and entertaining writer and completed several other accounts, most notably the story of, and observations from, his 1866-1867 inspection tour for the Quartermaster's Office of the Army of the West, which he called The Great West and Pacific Coast (1877). He also wrote an history of the Pennington School. A devout Methodist, he wrote several articles on subjects like "Hymns of the Ages" for various religious publications.
Back in his Trenton law office, Rusling was a New Jersey pension agent between 1869 and 1877. He was also a tax commissioner of his home state in 1896. He served as a trustee of Dickinson College from 1861 to 1883, and then again from 1904 until his death. At his fiftieth class reunion, he endowed the senior prize at the College which bears his name. He had already received an honorary doctorate from his alma mater in 1899.
He married Mary Freeman Winner of Pennington, New Jersey in 1855 and, after her death, later married Emily W. Wood of Trenton in June 1870. He and his second wife had a son and a daughter. James Fowler Rusling died at his home in Trenton on April 1, 1918, two weeks before his eighty-fourth birthday. He was buried in the Riverview Cemetery in that city.