John Carroll Parent, Sr., was born Jean Baptiste Francois Xavier Parent on August 11, 1885, in Brunswick, Maine. He changed his name to John Carroll Parent when he enlisted in the United States Army in 1906. One of six children of French-Canadian parents, Parent was raised bilingually, speaking both French and English in the home. At least one of his siblings, Edward Joseph Parent, also served in the United States Army.

Early in his service, Parent was assigned to Troop L, 6th Cavalry Regiment, stationed at Fort Keogh, Montana. While he was stationed at Fort Keogh, Troop L and Troop M, comprised of approximately 120 men, conducted a campaign against the Ute people. In 1907, Parent left California aboard a troop transport ship en route to the Philippine Islands. While stationed in the Philippine Islands, 1907-1910, Parent set up a telephone system on the island of Jolo. In the province of Sulu, Parent’s troop was assigned to protect the American tutor for the Sultan’s children. The tutor refused the Army’s protection, was subsequently ambushed and killed. Upon return to the United States, Parent was stationed at Fort Huachuca, Arizona, and was assigned to a patrol along the United States border with Mexico from 1911 to 1913, during the Mexican Revolution.

In 1914, Parent returned to civilian life and worked as a Forest Ranger and as an immigration inspector with the United States Customs Service. He also met and married his wife, Nellie. In 1917, after the United States entry into World War I, Parent returned to the military and earned a commission. He was assigned to the Military Police, and served as an instructor at the Presidio in San Francisco, California. He then transferred to Camp Lewis, Washington, where he became acting adjutant in the 91st Division. Parent was next sent to Paris, France, in advance of the 91st Division, to serve as assistant to the adjutant of the advanced section, under Major Lohrs, and then as aide-de-camp to General W.R. Sample. He also served as aide-de-camp to Colonel E.R. Warner McCabe, whom Parent first met in the Philippines, when McCabe was a Second Lieutenant and commander of Troop K. Parent was detailed to Headquarters to organize the Secret Service, working with Major Allan Pinkerton II (of the Pinkerton Detective Agency) beginning in Tours, France, in 1918. Parent organized and commanded four companies of criminal investigation units in major cities throughout France. Bernard Flood (who would go on to become Chief of Detectives in New York City) and Captain Arthur A. Hopkins worked with Parent. Hopkins and Parent had worked together as immigration inspectors in Arizona. Also stationed in France during World War I was writer and poet, Alfred Damon Runyon, who had served in Troop L in the Philippines with Parent. Runyon gave Parent a poem referencing their combat missions in the Philippines titled "The Sergeant's Prayer."

After World War I, Parent returned home to his wife and two children and to his job with the US Customs Service. Parent died on August 21, 1961.