He graduated West Point in 1842, ranking 52 out of 56 in his class. Assigned to the infantry, he served in garrison and on the frontier, participating in a great deal of Indian fighting. In one fight with the Comanches, he was seriously wounded 4 times. He had won 2 brevets in the Mexican War, being wounded at the City of Mexico. Transferring to the cavalry in 1855, he was
wounded in Indian fighting in 1858 near Wichita Village, Indian Territory.
Resigning as a major in the 2nd Cavalry on January 31, 1861, he offered his services to his native state. Van Dorn was promoted to a Brigadier General in the Provincial Confederate Army with the Mississippi State Troops in January 1861, and a major general with them in February. He was commissioned as the Colonel of C.S.A. Cavalry on March 16, 1861, and put in charge of the forts below New Orleans.
Early in the war, he commanded in Texas where he seized U.S. property and received the surrender of regular army detachments. Promoted rapidly to brigadier and major general, he was ordered to Virginia where he led a division near Manassas.
Early in 1862, he was sent to command in Arkansas in order to get Gens. Ben McCulloch and Sterling Price to cooperate. Launching an attack at Pea Ridge, he was repulsed after 2 days of fighting. He was then ordered east of the Mississippi River, but he arrived too late to take part in the fighting at Shiloh but participated in the unsuccessful defense of Corinth.
In the summer of 1862, he successfully defended Vicksburg but failed in his designs on Baton Rouge when the attack under Gen. John C. Breckinridge failed.
Another failure occurred when he attempted to retake Corinth in October 1862. By this time many Southerners were disenchanted with him, and he was placed in charge of the mounted troops under Pemberton. His raid on Holly Springs, was a major factor in ending Gen. Ulysses S. Grant's campaign in central Mississippi.
Moving his division into middle Tennessee, he was killed at Spring Hill on May 7, 1863, by Dr. George B. Peters for "violating the sanctity of of his home" with the physician's wife. Van Dorn's friends said that he was shot in the back, in cold blood, and for political reasons.
Van Dorn was of the Confederacy's most promising general officers early in the Civil War, but he proved to be a disappointment.
Colonel - March 16, 1861
Brigadier General - June 5, 1861
Major General - September 19, 1861
Department of Texas (April 21 - September 4, 1861)
Division, I Corps, Army of the Potomac (October 4-22, 1861)
1st Division, Potomac District, Department of Northern Virginia (October 22, 1861 - January 10, 1862)
Trans-Mississippi District, Department #2 (March 4 - June 20, 1862)
Department of Southern Mississippi and East Louisiana (June 20 - July 2, 1862)
District of the Mississippi, Department #2 (July 2 - October 1, 1862)
Army of West Tennessee, Department of Mississippi and East Louisiana (October 1862)
I Corps, Army of the Department of Mississippi and East Louisiana (December 1862)
Cavalry Division, Army of the Department of Mississippi and East Louisiana (January 13 - 20, 1863)
Cavalry Corps, Department of Mississippi and East Louisiana (January 20 - February 1863)
Cavalry Division, Army of Tennessee (February 25 - May 7, 1863)