Rank : Captain
Regiment : United States. Army--Engineer Corps
Service : 1861 August 19-1866 July 10
A Prussian by birth, and apparently a refugee of 1848, William Kossak leapt immediately into service in the Civil War with a commission as Lieutenant in the 5th Missouri Infantry on May 20, 1861. By August of that year, he had earned a promotion to Captain and Additional Aide-de-Camp in the volunteer Engineers, working on the staffs of the great generals of the western theatre, including Grant and Sherman.
Kossak remained extremely active throughout the war, and his record amounts to a virtual roll of the great campaigns in the west. He served at Forts Donelson and Henry, Shiloh, Corinth, Vicksburg, the Atlanta Campaign, and the March to the Sea. For much of this time, Kossak reported closely to General Sherman, earning personal commendations form both Sherman and Grant. He rose to his highest position, when he became Chief engineer of the 17th Army Corps during Sherman's campaigns in Georgia.