James garfield, rosecrans's chief of staff, would later become a famous
secretary of state
governor
president
senator

He would become President.  He was with Rosecrans they fought in the Civil in the Tullahoma Campaign and the Battle of Chickamauga.  Later Rosecrans was replaced by General George Thomas and was promoted to Major General.  Later on he turned to politics and was elected president in 1881.  Among his achievements was strengthening the Navy, civil service reform, revival of presidential authority against senatorial courtesy in executive appointments and clearing the post office of corruption.  He was later shot and killed by Charles Guiteau on July 2, 1881.

He gathered information from primary sources.