Brooks was born in New Lisbon (now Lisbon), Ohio, and was educated in public schools. He graduated from the United States Military Academy, ranking 46th out of 52 students in the Class of 1841. Appointed a second lieutenant, he served on garrison and frontier duty.
Promoted to divisional command, Brooks led the 1st Division of VI Corps at Fredericksburg and Chancellorsville. In June 1863, he was promoted to major general of volunteers, but this was later revoked. This demotion has been blamed on Brooks's being involved in intrigues by VI Corps commanders against Maj. Gen. Ambrose Burnside after Fredericksburg.[1] During the Gettysburg Campaign, he commanded the Department of the Monongahela, with his headquarters in Pittsburgh. He supervised the construction of a series of earthworks to protect the city from a possible Confederate raid. Returning to field duty in the late spring of 1864, Brooks commanded the 1st Division of XVIII Corps at Cold Harbor and Petersburg. In July 1864, he was forced to resign from the Army due to poor health and returned home.
Battle
April 29, 1863: Second Battle of Fredericksburg
Maj. Gen. John Sedgwick was left near Fredericksburg with the VI Corps, the I Corps, and the II Corps division of Brig. Gen.John Gibbon. Hooker's plan called for Sedgwick to demonstrate near the city in order to deceive Lee about the Union plan. The VI and II Corps seized control of several crossings on April 29, 1863 laying down pontoon bridges in the early morning hours, and the divisions of William T. H. Brooks and James S. Wadsworth crossed the river. The I Corps was ordered to reinforce the main army at Chancellorsville during the night of May 1. During the evening of May 2, 1863 Sedgwick received orders to attack Early with his remaining forces.[2]
May 3, 1863: Fredericksburg and Salem Church
At 7 a.m. on May 3, Early was confronted with four Union divisions: Brig. Gen. John Gibbon of the II Corps had crossed the Rappahannock north of town, and three divisions of Sedgwick's VI Corps—Maj. Gen. John Newton and Brig. Gens. Albion P. Howe and William T. H. Brooks — were arrayed in line from the front of the town to Deep Run. Most of Early's combat strength was deployed to the south of town, where Federal troops had achieved their most significant successes during the December battle. Marye's Heights was defended by Barksdale's Mississippi brigade and Early ordered the Louisiana brigade of Brig. Gen. Harry T. Hays from the far right to Barksdale's left.[3]
May 3, 1863: Battle of Salem Church
At first Sedgwick believed that he faced a single brigade of infantry, so about 3:30 p.m. he attacked the Confederate positions with only William T. H. Brooks division. Brooks succeeded in driving back McLaws's right flank but a counterattack stopped the Union attack and forced Brooks to retreat back to his original position; sunset ended the combat before any further units were involved. During the night, Lee ordered Early to attack Sedgwick's left flank in the morning, while McLaws attacked the Union right.[4] Also during the night, Sedgwick received no further orders from Hooker other than authorization to retreat across the river if Sedgwick thought the move was necessary.[5]