With the outbreak of the Civil War, Wild enlisted in the Union Army as a front-line officer, preferring to command troops rather than to treat their injuries.

At the Battle of South Mountain, Wild suffered another severe wound, one that necessitated the amputation of his left arm.

The brigade, headquartered in Norfolk, comprised the 55th Massachusetts Infantry, and the 2nd and 3rd North Carolina Colored Volunteers (which later became renumbered as the 36th and 37th U.S.

[5] Transferred to the Army of the Potomac in 1864, Wild and his black soldiers participated in the Overland Campaign and the subsequent Siege of Petersburg, Wild's men constructed and manned Fort Pocahontas, an earthen-walled Virginia fort on the James River that during the Battle of Wilson's Wharf withstood an attack on May 24 by Fitzhugh Lee's Confederates.

They were a part of the large force of black troops under Godfrey Weitzel that occupied the former Confederate national capital, Richmond, Virginia, holding that city through the end of the war.

Wild's men were among those troops who witnessed the historic visit of President Abraham Lincoln to Richmond following the city's fall to the Union forces.

[8] Further, he was part of the arrest and trial of two local white men for the murder of a newly freed black woman that failed to convict.

[8] In late May 1865, Wild traveled from Macon to Washington, GA to investigate reports that the local white population was still holding black citizens as slaves.

[15][note 1] While no information resulted from the torture of the Chenault men, they were arrested when investigation revealed substance to the reports of their abuse of their former slaves.

[15] Wild continued angering the local white plantation class through the confiscations of properties under the operation of the bureau.

When the Chennault family's attorney reached the military government in Augusta with details of their treatment, this news combined with the complaints from wealthy local white citizens led to his dismissal from his post.