His men played a key role on the first day of the Battle of Gettysburg in driving back the Union XI Corps.

At the age of 16, Doles loaded a stagecoach with his brother, bound to join the Army in the Mexican–American War, but he was intercepted by his father before the coach could depart.

When General Roswell Ripley fell with a wound at the Battle of Antietam defending Mumma's Farm, Doles assumed temporary command of the brigade and led it in an assault into the southern end of the Miller cornfield.

On July 1, 1863, Doles attacked the line of the Union XI Corps in fields near Rock Creek north of Gettysburg, driving their adversaries back over a mile.

Pressure from Doles, as well as from fellow Georgian John B. Gordon and other brigades, eventually forced much of the XI Corps to collapse and retire to Cemetery Hill.

[5] During the Battle of Cold Harbor in June, a Union sharpshooter shot Doles in the left breast as he was inspecting the Confederate entrenchments near Bethesda Church, Virginia.