Davis entered the war as a commander in the U.S. navy with thirty years of experience. He was assigned to command the South Atlantic Blockading Squadron in November 1861, until he was transferred to the Upper Mississippi Gunboat Flotilla in May 1862. During his service, he was involved at Port Royal, Memphis, Vicksburg, and Yazoo River. In late 1862, he moved to Washington as the head of the Bureau of Navigation. He served in this position after the end of the war.
