Wallace was born to a prominent local family. His father, David Wallace, later served as Indiana Governor. He attended Wabash College in Crawfordsville, Indiana and worked as a clerk. During the Mexican War, he served as a second lieutenant in the lst Indiana but saw only minor action.
In 1849, he was admitted to the bar in Indiana and 7 years later, he entered the Indiana state senate.
At the start of the Civil War, Wallace helped raise troops in Indiana.
When the Civil War began, he returned to military service, and was able to make his way through the ranks largely because of his political connections. His career got off to a promising start when he routed an inferior Confederate force at Romney, Virginia. Promoted to Brigadier General, he was given charge of a newly organized division in the midst of the operations against Fort Donelson and Fort Henry. After the battles, he was promoted to major general.
His most controversial command, however, came at the Battle of Shiloh, where he was put in charge of a 7,000-man division in the army of Major Gen. Ulysses S. Grant. Wallace's division had been left as reserves at a place called Stoney Lonesome to the rear of the Union line. At about 6:00 A.M., when Grant's army was surprised and virtually routed by the sudden appearance of the Confederate army under Gen. Albert S. Johnston, Grant sent orders for Wallace to move his unit up to support the division of Major Gen. William T. Sherman.
Wallace claimed that Grant's orders were unsigned, hastily written, and overly vague. There were two paths by which Wallace could move his unit to the front, and Grant (according to Wallace) did not specify which one he should take. Wallace chose to take the upper path, which was much less used and in considerably better condition, and which would lead him to the right side of Sherman's last known position. Grant later claimed that he had specified that Wallace take the lower path, though circumstantial evidence seems to suggest that Grant had forgotten that more than one path even existed. Wallace redeemed himself on the second day, but a scapegoat was needed for the near disaster the first day and he was blamed. His mistakes and poor judgment earned the criticism of Major Gen. Ulysses S. Grant.
At first, there was little fallout from this. Wallace was the youngest general of his rank in the army, and was something of a "golden boy." He was also rather a braggart. Soon, civilians in the North began to hear the news of the horrible casualties at Shiloh, and Army command needed a scapegoat to explain them. Both Grant and his command replacement, Major Gen. Henry W. Halleck, placed the blame squarely on Wallace, saying that his incompetence in moving up the reserves had nearly cost them the battle. Sherman, for his part, remained mute on the issue. Wallace was removed from his command, and reassigned to much less glamorous duty on the east coast. In July of 1864, he produced mixed results in the Battle of Monocacy Junction, part of the Valley Campaigns of 1864: his army (the Middle Department) was defeated by Major Gen. Jubal A. Early, but was able to delay Early's advance toward Washington, D.C., sufficiently that the city defenses had time to organize and repel Early.
Personally, Wallace was devastated by the loss of his reputation as a result of Shiloh. He worked desperately all his life to change public opinion about his role in the battle, going so far as to literally beg Grant to "set things right" in Grant's memoirs, which he refused to change.
Wallace was removed from combat duty and sent home to await further orders, he offered his services to Indiana Governor Oliver P. Morton and was appointed to the administrative position of commander of the Middle Department. He took temporary command of a regiment during the emergency posed by Major Gen. E. Kirby Smith's invasion of Kentucky. With Cincinnati threatened, Wallace was placed in charge of a mostly civilian defense force. Through a show of tremendous energy, he was able to save the city without a major fight. Wallace returned to the field , leading forces at the Battle of Monocacy and in the 1864 Shenandoah Valley Campaign .
At the close of the war, Wallace sat on the court-martial which tried the President Abraham Lincoln conspirators and presided over the trial which sent Andersonville Prison Capt. Henry Wirz to the gallows. On November 30, 1865, he resigned from the U.S. service. He joined the cause of the Mexican liberals against the French occupation. He tried to raise money and troops and even accepted the title of major general from the Juarez group. Although he hoped to lead the Republican troops to glory, he saw no action in the conflict.
Wallace held a number of important political posts during the 1870s and 1880s. He served as Governor of New Mexico Territory from 1878-81, and as U.S. Minister to Turkey from 1881-85. As Governor he offered amnesty to many men involved in the Lincoln County War; in the process he met with "Billy the Kid."
Wallace penned the novel that made him famous in 1880: "Ben-Hur: A Tale of the Christ". It grew to be the best selling American novel of the 19th century.
Brigadier General USV- September 3, 1861
Major General USV- March 21, 1862
adjutant general of Indiana (April 1861)
Colonel, 11th Indiana (April 25, 1861)
Colonel, 11th Indiana (reorganized August 31, 1861)
Brigadier General, USV (September 3, 1861)
3rd Division, District of Cairo, Department of the Missouri (February 14-17, 1862)
major general, USV (March 21, 1862)
3rd Division, Army of the Tennessee (February 17-June 1862)
VIII Corps, Middle Department (March 22, 1864-February 1,1865 and April 19-August 1, 1865)
Middle Department (March 22, 1864-February 1,1865 and April 19-June 27, 1865)