John McArthur was born November 17, 1826, in the parish of Erskine on the River Clyde in Renfrewshire, Scotland. He learned his father's trade of blacksmithing, and at the age of twenty-three he emigrated to the United States and settled in Chicago where he soon became successful as proprietor of the Excelsior Iron Works. During the antebellum years he interested himself in a militia company called the "Chicago Highland Guards" of which he was captain in 1861. On May 3, 1861, he was appointed colonel of the 12th Illinois Infantry, a ninety-day regiment which was remustered in August to serve three -years. It inaugurated its military service by garrisoning Cairo, and before the year was out McArthur was directing the 1st Brigade of C. F. Smith's 2nd Division, District of Cairo, as the army under Ulysses S. Grant was then known. From the capture of Forts Henry and Donelson in February, 1862, until the end of the war, the tall, brawny Scot compiled a combat record second to none in the capacity in which he served. Promoted brigadier general in March, 1862, he succeeded to command of W. H. L. Wallace's division after the latter was mortally wounded on the bloody field of Shiloh, and he led a division of the Army of the Tennessee under Edward Ord at Iuka and Corinth. He directed one of McPherson's XVII Corps's divisions during the Vicksburg campaign, and was commander of the city itself until August, 1864. On the fifth of that month he was ordered by W. T. Sherman to the Atlanta area to protect the latter's line of communications stretching north toward Chattanooga. In November he brought the 1st Division of the XVI Corps back to Nashville from Missouri where it had been occupied resisting Sterling Price's raid; the following month at the battle of Nashville, his four thousand men rolled up John B. Hood's left on the first day of the battle. For this exploit of "conspicuous gallantry and efficiency," he was brevetted major general. Thereafter he served under Edward Canby in the campaign which concluded the war and was stationed at Selma, Alabama, during the summer of 1865. His postbellum career was by no means so successful: he failed to revive his ironworks; the great Chicago Fire of 1871 occurred while he was commissioner of public works; and as postmaster of the city, he was further humiliated by the loss of Federal funds in a bank failure in which he was held personally liable by judicial decree. Prominent in Scottish and veterans organizations until his death, General McArthur died May 15, 1906, in Chicago and was buried in Rosehill Cemetery.
Reference: Generals in Blue. Lives of the Union Commanders by Ezra J. Warner. Louisiana State University Press. Baton Rouge.