By Year 1861 Ingalls is ordered to the a place that was part of the US when he joined Army, for the first time in his career . 1862 Peninsula Campaign. 1864 Wilderness and Petersburg. His skills and experience as a quartermaster would be sorely needed to supply the huge new 'Army of the Potomac'.
Professional soldiers seem to have all either been quartermasters or topographers.
This new crisis required the officers on both sides to be Generals and warriors, leading huge armies. This was something new, but not unfamiliar to them. The West Pointers had been drilled endlessly and schooled in the requisite skills that would serve them well in the 'rebellion'. The one difference that set the Confederate army apart from the Union is that they had generals that were great leaders. The Yankees had a huge problem with politics and rank.