Who was the leading Union general during the American Civil War and later became the eighteenth President of the United States?

Ulysses S. Grant was the leading Union general during the American Civil War, known for his aggressive tactics and effective command of Union forces. He played a crucial role in several key victories, such as the Siege of Vicksburg and the Battle of Chattanooga, which significantly contributed to the Union's overall success in the war.

Grant's leadership style was characterized by a willingness to engage the enemy and sustain pressure, contrasting with other generals who may have been more cautious. After the war, he became a national hero and was elected as the eighteenth President of the United States, serving from 1869 to 1877. His presidency faced numerous challenges, including Reconstruction efforts and various scandals, but he remained an important figure in shaping the post-war United States.