Early Years

McDowell was born on October 15, 1818, in Columbus, Ohio, the son of Abram and Eliza Seldon McDowell. In his youth his family emigrated to France, where he attended the College of Troyes in Troyes, southeast of Paris. Returning to Ohio, where his father became mayor of Columbus, McDowell sought and obtained admission to the U.S. Military Academy at West Point, New York. On July 1, 1838, he graduated ranked twenty-third in a class of forty-five. Fellow cadets included Pierre G. T. Beauregard of Louisiana, who would command the Confederate forces at the First Battle of Manassas. From 1841 to 1845, McDowell taught tactics at West Point and rose to become adjutant of the academy. On November 13, 1844, he married Helen Burden of Troy, New York, and during the Mexican War he served on the staff of his wife's acquaintance, Major General John E. Wool, winning the brevet rank of captain for gallantry at the Battle of Buena Vista (1847).

Appointment to Command

Following the war in Mexico, McDowell moved steadily through the administrative ranks of the army, gaining a prestigious position on the staff of Commanding General Winfield Scott. When the Civil War broke out, McDowell was a major in the adjutant general's office. His position at Scott's right hand, his twenty-three years of active service, and his status as a military intellectual (an acquaintance called him "one of the most thoroughly educated and accomplished soldiers I ever met"), seemed to assure him of a successful wartime career. Yet he had no experience in field operations, nor did he look the part of a great captain. His reputation as a "Gargantuan feeder" had given him a notable paunch and made him susceptible to digestive ills. At times he seemed consumed by nervous energy that caused his face to flush and his speech to thicken, causing strangers to suspect that the teetotaling Ohioan was a drunkard. He also lacked the requisite communication skills; he could be sharp and abrupt with subordinates, one of whom criticized his "too frequent forgetfulness of the courtesy due even to a common soldier."

Despite his shortcomings, McDowell rose to command the first large influx of soldiers to reach the nation's capital. The aged General Scott was too infirm to lead this force, known as the Army of Northeastern Virginia, and his first choice to command it, Colonel Robert E. Lee, turned him down to join the defense forces of his native Virginia. Promoted to brigadier general in the Regular Army on May 14, 1861, McDowell spent two months laboring to organize, equip, train, and discipline a mob of raw but eager recruits.

First Battle of Manassas

By late in June 1861, a smaller Confederate army had assembled in northern Virginia, only about twenty miles southwest of Washington. When Scott ordered McDowell to submit a plan to defeat this force, the Ohioan complained that his men were too inexperienced to take the offensive. Scott brushed aside his objection: "You are green, it is true; but they are green, also; you are all green alike." McDowell gave in to his superior's demands, although he would lament that "I had no opportunity to test my machinery; to move it around and see whether it would work smoothly or not … I wanted very much a little time; all of us wanted it. We did not have a bit of it."

Urged on by Scott, by hawkish politicians, and by editors such as Horace Greeley, whose New York Tribune clamored for a march "On to Richmond," on July 16, McDowell reluctantly led his 36,000 would-be soldiers out of Washington. Confirming his direst suspicions, the recruits straggled and looted all the way to Bull Run. When McDowell issued strict orders to stop violating civilian property, his men called him a Southern sympathizer. On July 17 an equally inexperienced subordinate turned a reconnaissance of the enemy's right flank into an attack at Blackburn's Ford that met a demoralizing repulse. Four days later, McDowell led the main body of his army on a long, exhausting march across difficult ground to attack Beauregard's left flank.

The subsequent attack across Bull Run was poorly executed but nevertheless achieved surprise. For much of the morning the enemy flank appeared on the verge of collapse. Frantically committed reinforcements shored up the sector; they included thousands of troops recently arrived by troop train from the Shenandoah Valley under General Joseph E. Johnston. A Union army under Major General Robert Patterson had been ordered to keep Johnston occupied, but the wily Virginian had slipped away. His junction with Beauregard enabled the Confederates to oppose their attackers on virtually equal terms.

For hours the fighting below Bull Run continued at white heat but without decisive effect. McDowell erred by committing his troops piecemeal rather than in powerful combinations, enabling Beauregard to parry his every thrust. In midafternoon the fighting turned when McDowell ordered two artillery batteries to occupy ground so close to the enemy's line that they were quickly overrun. Soon the exhausted, parched Union troops began a retreat that turned into panic-stricken flight. Though neither overwhelmed nor routed, they streamed back to Washington in company with civilian spectators, including government officials who had come out to witness what they supposed would be a Union victory.

In the aftermath of the debacle, McDowell faced a torrent of criticism and censure. He was faulted not only for tactical mistakes, but also for remaining in the rear throughout the fight instead of exercising personal command. For a time McDowell feared being shelved, but he retained the support of U.S. president Abraham Lincoln. Instead, he was quietly demoted to division command under his hastily summoned successor, Major General George B. McClellan. In March 1862, McDowell was promoted to major general to command a corps in McClellan's Army of the Potomac.

Service under McClellan and Pope

From the first, McDowell and McClellan clashed. For one thing, they were political opposites: the new commander was a staunch Democrat while McDowell displayed Republican leanings. McDowell regarded McClellan as an arrogant usurper, while McClellan considered his subordinate a mediocre tactician as well as insufficiently appreciative of the "forbearance and kindness" shown him by his new superior. Their relationship reached its nadir when, at the start of McClellan's Peninsula Campaign, Lincoln, fearing that "Little Mac" had stripped Washington of defenders, ordered McDowell's command to remain within supporting distance of the capital. McClellan suspected that McDowell had conspired with the president to deny him 40,000 troops, whose withholding he considered partially responsible for the army's failure to take Richmond.

McDowell gained an opportunity to salvage his reputation when in June he was named commander of the Third Corps in Major General John Pope's newly organized Army of Virginia. The assignment, however, returned McDowell to the fields around Bull Run where he had tasted defeat and humiliation. At Groveton, Virginia, on August 28, a portion of his command was bested by troops under Confederate general Thomas J. "Stonewall" Jackson. The following day, the first day of the Second Battle of Manassas, the corps fought erratically against Jackson's outnumbered but combative troops. Late that morning McDowell gave vague and ambiguous instructions to a junior colleague, Major General Fitz-John Porter, which helped embroil Porter in a celebrated controversy that cost him his career.

McDowell also erred by failing to inform Pope that an enemy column under Confederate general James Longstreet was en route to join Jackson. On August 30 Longstreet delivered a crushing attack that broke Pope's left flank and forced him into retreat. McDowell partially redeemed himself by cobbling together a rear guard that repulsed several attempts to cut off the army's withdrawal to Washington. McDowell, however, had previously left a critical sector of his position undefended, an act that some historians consider the most critical tactical blunder of the battle.

In defeat McDowell was again assailed by critics, many of whom resurrected the canard that he was an enemy in disguise. A well-publicized rumor had a fellow general shooting him for treason. One soldier recalled that throughout the retreat "the most profane oaths were uttered in reference to [McDowell's] conduct … There was scarcely a moment during the march in which I did not hear the epithets 'villain,' 'traitor,' or 'scoundrel,' applied to his name."

Later Years

Republican leaders continued to support McDowell, but public opinion dictated his removal from command. Lincoln found an opportunity to relieve him after McDowell requested a formal investigation into his conduct at Second Manassas. In February 1863, the two-month proceeding ended in McDowell's exoneration, but his recent miscues had received so much notoriety that his field career was effectively over. During this same period, McDowell testified at the court-martial that convicted Fitz-John Porter of dereliction of duty, leading to his dismissal from the service. In defending himself against charges that he had abetted Porter's alleged delinquencies at Second Manassas, McDowell deliberately misled the court and may have perjured himself.

Through early 1864 McDowell headed a series of minor administrative posts. In May he was sent to San Francisco to command the Department of the Pacific, a vast fiefdom that by all accounts he supervised creditably. After war's end, he headed military departments in the east and south as a major general in the regular service. In 1876 he returned to California as commander of the Division of the Pacific. He retired from the army in 1882 to pursue hobbies including landscape gardening, which led to his appointment as park commissioner of San Francisco. He died there of pyloric disease on May 4, 1885.