John O'Fallon was born on November 17, 1791, near Louisville, Kentucky. His father, Dr. James O'Fallon, a native of Ireland, had married in 1791 Frances Eleanor Clark, a sister of the two celebrated brothers, George Rogers Clark and William Clark, and of the union were born two children, John and Benjamin.
The education of young O'Fallon and his brother was looked after by their uncle, William Clark, whose correspondence with John, then in school, contains the following advice: "I must recommend you to court the company of men of learning, sober, sedate and respectable characters. You will not only gain information from them but respectability and influence. " He was a student in Kentucky, first at an academy in Danville and later at an incipient college near Lexington.
After college, John O'Fallon entered upon a military career in 1811. He served as a private in General William Henry Harrison's campaign of that year against the Indians. Wounded severely in the battle of Tippecanoe, he went for convalescence to St. Louis, where he entered the service of his uncle William, at that time superintendent of Indian affairs in the West. During the War of 1812 he was in turn ensign, second lieutenant, first lieutenant, and captain; he also became private secretary to General Harrison, his acting deputy adjutant-general at Fort Meigs, and his regular aide-de-camp.
Later, when, in the heat of political controversy, attempts were made to belittle Harrison's military record, the General appealed to O'Fallon, asking him to write from his intimate personal knowledge for publication a letter in which the actual facts regarding Harrison's participation in the battles of Tippecanoe, Fort Meigs, and the Thames should be truthfully set forth. This request O'Fallon complied with in a remarkable letter, dated St. Louis, February 26, 1840, in the course of which he observes: "I doubt whether there is another living who has possessed equal opportunities with myself of forming a correct opinion of General Harrison's military character. I served under him during the greater part of the period he was in active service, near his person, commencing with the Tippecanoe expedition and continuing to its termination. I can safely say that I never in my life saw a braver man in battle, one more collected, prompt, and full of resources than General William Henry Harrison. "
Having been in command at Malden, which Canadian post he delivered to the British at the end of the War of 1812, O'Fallon in 1818 resigned at Mackinaw his commission in the army, prospects of promotion being slender, and went to St. Louis with the ambition, which he frankly avowed, of making a fortune in business. In this endeavor he eminently succeeded, becoming in turn Indian trader, army contractor, and merchant on a large scale.
Within a year of his arrival in the West, he wrote to his mother that he was making money "at the rate of $1000 a month. " Shrewd real-estate investments added largely to his means and in the end he became one of Missouri's wealthiest citizens. His reputation for personal integrity was widespread, and this, together with his well-known business acumen and great private fortune, gave him a position of unique influence in the community. He was president of the St. Louis branch of the United States Bank during the entire period of its existence, and president also of the Mississippi & Ohio Railroad and of the North Missouri Railroad.
His benefactions were constant and included liberal gifts to O'Fallon Polytechnic Institute, St. Louis and Washington universities, and to churches of various denominations, especially his own, the Methodist Episcopal Church South. "The fact is, " wrote Abel Rathbone Corbin to him in 1851, "you have done so much for religion, scientific and public purposes that it is difficult to make out a list of beneficiaries; not a fire-company, not a library association, not a church, not anything but appeals to Col. O'Fallon in their hour of need. "
John O'Fallon was the wealthiest person in St. Louis, Missouri in the 19th century. O'Fallon was president of the St. Louis branch of the United States Bank, the Mississippi & Ohio Railroad, and of the North Missouri Railroad. In later life, O'Fallon donated land for Saint Louis University, Washington University in St. Louis, O'Fallon Park. He also founded O'Fallon Polytechnic Institute and financially supported Washington University's medical college and churches of various denominations, especially his own, the Methodist Episcopal Church S.
John O'Fallon was twice married: in 1821 to Harriett Stokes, an Englishwoman; and, on March 15, 1827, to Ruth Caroline Sheets of Maryland. He had four sons and one daughter.
