Why was Ulysses S. Grant famous?

Ulysses S. Grant achieved ever-lasting fame because of his success as a military leader during the Civil War (1861–1865). He endured many setbacks both before and after the war.
Born into a modest family in Ohio, Grant was not an outstanding figure in his youth. He was adept at horseback riding but not much else. He did not want to work in his father's tannery business, so his father sent him to West Point. His academic performance there was mediocre. He served the country well in the Mexican War (1846–1848). In the 1850s, however, his military career soured, and he failed at numerous business ventures.
In the Civil War, he emerged from obscurity to lead the North to victory. His campaign at Vicksburg was masterful. Also, he was the only Union general who was not intimidated by Robert E. Lee, the Confederate general.
After the war, Grant failed as president and in his life after the White House. His presidency is remembered for its corruption. After serving as president, he went bankrupt.
Grant's failure before and after the war, however, are not as significant as his brilliant record during the Civil War. Without his leadership, the North could have lost the war.