Fish had several important roles during the American Civil War. Fish's private secretary was involved in the attempt of the merchant ship "Star of the West" to bring relief supplies to Fort Sumter in Charleston harbor. During this period, Fish often met with General Winfield Scott, commander-in-chief of the US Army. Fish was dining with Scott in New York when a telegram reported that Confederates had fired on "Star of the West". Fish said that this meant war; Scott replied "Don't utter that word, my friend. You don't know what a horrid thing war is."