McConnel was born on November 11, 1826 in what was then Morgan but is now Scott County, Illinois. He was the son of Murray and Mary Mapes McConnel. His father was a self-made pioneer lawyer who served in both branches of the state legislature and in the Black Hawk War, and was appointed by President Pierce one of the auditors of the United States Treasury, a post which he held for about five years.
Education
John studied law under his father and at the Transylvania law school, from which he was graduated in 1843 in a class of twenty-nine.
Career
John enlisted for service in the war with Mexico and before leaving the rendezvous of his company at Alton, Ill. , he was made first lieutenant. After the battle of Buena Vista, where he was wounded, he became captain in the 1st Illinois Volunteers. Returning to Jacksonville, he took over his father's practice, but he was as much interested in creative writing as in his professed deity, the law. His first works were melodramatic novels. Grahame: or Youth and Manhood (1850) is an improbable tale which leaves the modern reader quite out of sympathy with any of the characters or situations. Talbot and Vernon (1850), a tale of love intrigue and the war in Mexico, with some excellent descriptions of that region and of court scenes in the West, and The Glenns: A Family History (1851), interesting for the author's pictures of the Southwest and the turbulent society of frontier Texas, throw valuable light on the social history of the period. Western Characters: or Types of Border Life in the Western States (1853) is a valuable descriptive volume which portrays the picturesque figures of the frontier. At the time of his premature death in 1862 he was engaged in a study to be entitled "History of Early Exploration in America, " treating especially the work of the early Roman Catholic missionaries.
Achievements
McConnel known as first Lieutenant and was promoted Captain after the battle of Buena Vista.