Tulis neraskeun pikeun ayat ieu - Anjeunna ngagabung Angkatan Darat Uni salaku swasta di Company E tina 49th New York Sukarelawan Infanteri dina Juni, 1861, naek ka sarjan teratur. Kalayan Tentara Potomac unitna milu dina perang nu kaasup Young's Mill, Yorktown, Williamsburg, Mechanicsville, Fair Oaks
, Gaines's Mill, Savage's Station, Malvern Hill, Second Bull Run, South Mountain, Antietam, Fredericksburg, Williamsport, Gettysburg, Mine Run, Wilderness, Cold Harbor, Petersburg jeung nu lianna. Walsh dipanjara salila operasi ngalawan Welden Railroad teu lila saméméh kadaluarsana istilah enlistment sarta jadi tahanan di Belle Isle, Libby Panjara, Andersonville, Savannah, Castle Pinckney jeung Florence Stockade, saméméh ditukeurkeun jeung balik ka Annapolis, Indiana, di mana manéhna ieu honorably discharged May 5, 1865. Di sawatara titik sanggeus ieu, anjeunna spent dalapan taun gawe di "Wisconsin Nagara Journal" di Madison.