After seeing action at the First Battle of Bull Run (First Manassas), Walker became the chief of artillery to General A.P. Hill. Lindsay Walker, as he was known, amassed a lengthy combat record, serving in every one of the Army of Northern Virginia's major battles except the Seven Days Battles (he was ill at the time).
Following his participation in the First Battle of Bull Run, Walker rose to become the chief artillery officer for General A.P. Hill. Lindsay Walker, as he was known, gained extensive combat experience by serving in all but one of the Army of Northern Virginia's major battles, missing only the Seven Days Battles due to illness.