Theodore Roosevelt!

Theodore Roosevelt is a sickly child, but he puts himself through strenuous regimens and successfully builds his health and strength. He goes to Harvard and enthusiastically leads a vigorous life that includes hunting, ranching, law enforcement, reform, politics, writing, government service, and military combat. He becomes president at a young age and takes the lead in transforming that office into a center of activism. But he damages his health exploring South America, and dies at a young age after his son is killed in World War I.