John C. Carroll was born on February 6, 1889 to John Charles Carroll Sr. and Elizabeth Tatum Carroll about ten miles west of El Dorado, Union County, Arkansas. They were descendants of the earliest settlers of the county. He got his early education from public schools in El Dorado, and graduated high school in Stephens, Union County, Arkansas. He briefly attended Ouachita Baptist University in Arkadelphia before entering the University of Arkansas in 1909. Coming from a family of limited means, he had to work various jobs, including teaching two school terms in Union County, to help finance his school expenses. He graduated with honors and as president of his class at the University of Arkansas in 1916. While at the University of Arkansas he was president of the Lee Society, president of the Baptist Young People’s Union, member of the Student Council, Y.M.C.A. Cabinet member, and editor of the 1915 yearbook, The Cardinal.

After graduating from the University of Arkansas, Carroll attended Harvard Law School, where he earned his school expenses by working as a Proctor. However, after his freshman year, Carroll’s studies were interrupted by the American involvement in World War I. He joined the United States Army and served at Camp Devens in Massachusetts and Plattsburn in New York before being sent to France on October 9, 1917. He was commissioned a second lieutenant and assigned to the 102nd Machine Gun Battalion. He returned in May 1919 in command of his company because while fighting in France, Carroll’s superior officers had either been killed or wounded. He was honorably discharged and returned to Harvard Law School. There, Carroll met his wife, Ellen Welch of New Haven, Connecticut, and they married in 1921 after his graduation.

The newlyweds moved to El Dorado and together they had three children, John, Jean, and Mary. Carroll practiced law until he began pursuing a political career as city attorney in 1932. He was then elected municipal judge in 1934, a position he held until his death on November 10, 1936 in a car accident.