Abraham Lincoln, as the President of United States during the American Civil War, served as the commander-in-chief of all Union forces, including the armies and the navy. However, he did not directly command them in the field. Union armies were led by generals such as Ulysses S. Grant, William T. Sherman, and George B. McClellan, who were responsible for the strategic and tactical decisions during battles and campaigns. Lincoln oversaw the overall war effort, appointed military leaders, and made important strategic decisions in consultation with his generals.