Julius Peter Garesche du Rocher was born in Cuba on April 26, 1821. His grandfather Jean Garesche had added the name du Rocher from an estate of Julius's great-great-grandfather, after the custom of the younger sons of French nobles, in order to distinguish himself from his elder brothers. 'du Rocher' would later be dropped from the family name. Julius's father Vital Marie Garesche du Rocher married Mimika Louisa Bauduy, eldest daughter of Pierre Bauduy of Wilmington, Delaware, in September 1809. She was Catholic, and the Garesche family was staunchly Protestant. Born in Cuba, while Vital Marie was stationed there with the U.S. government, Julius was, baptized in a Catholic church since that was the only tolerated religion in the country at the time. In 1827, the Garesche family returned to the United States, and settled in New York. Then, some time in 1829 or 1830, the family relocated to Wilmington, Delaware, residing at Mimika's family home at Eden Park. For the next three years, Julius and his brother Alexander attended an academy on Quaker Hill kept by Samuel Smith.
In September 1833, Julius entered Georgetown College, Washington, D.C., at the age of twelve. To the relief of his mother, Julius's father had opted for a Jesuit school after all, when he did not find a satisfactory Protestant college. Julius' brother, Alexander John Peter, also attended Georgetown College (1835-1838), although he left before graduating. The boys' cousin, Peter Bauduy, son of their uncle Jean P. du Rocher Garesche, attended from 1833 to 1836, also without obtaining a degree. Later, Alexander's sons, William, Henry, and Edmund would also study at Georgetown. It was while he was at Georgetown that Julius formally converted to Catholicism. However, he was unable to complete his Georgetown education because of some financial problems his father experienced. Julius suggested that he might continue his education under the auspices of the U.S. Army as a cadet at West Point Military Academy. Judging this a most honorable profession, Vital Marie granted his permission, and in May 1837, Julius left Georgetown College for West Point. He graduated in 1841 and was commissioned second lieutenant of the 4th Artillery.
He then served in the Mexican War under General Taylor. He was promoted to first lieutenant in 1846; to Brevet captain, Assistant Adjutant General, in 1855; to Brevet Major, in May 1861; and to lieutenant colonel in 1862. On November 9, 1862, Julius was appointed chief of staff to General William Starke Rosecrans, commander of the 14th Army Corps, also designated the Army of the Cumberland. In this capacity he served until his death on December 31, 1862, when he was beheaded by a cannon ball at the battle of Stone River, Murfreesboro, Tennessee. Initially buried on the battlefield (on the site of which a monument was eventually erected in memory of Garesch‚ and his fallen comrades), Julius's remains were later removed by his brother Alexander and buried at Mt. Olivet Cemetery in Washington, D.C. The Society of St. Vincent de Paul which Julius had helped found, met with the Georgetown College Philodemic Society and resolved, in January 1863 to erect a monument over his tomb at Mt. Olivet. Julius Garesche was married to Mariquitta de Laureal, February 17, 1849. They had eight children, Marie Pierre Jules ('Julio'), Louise, Marie, Octavie ('Tavie,' became Sister Augustine of the Holy Face), Louis, Edgar, Laureal, and Adele (became Sister Francis Joseph). Only Marie, Octavie, Louis and Adele survived infancy. Mariquitta survived her husband eight years, dying in St. Louis on February 16, 1871. She was buried in Calvary Cemetery, but was reburied with her husband at Mt. Olivet by her son Louis in November 1922. Here, her children Edgar and Laureal are also buried.