Teddy Roosevelt’s highest military rank was lieutenant colonel in the U.S. Army, though he was often called Colonel Roosevelt because he led the Rough Riders.

Quick context

He first served in the New York National Guard, where he rose to captain, and later was appointed lieutenant colonel during the Spanish-American War.

Why people remember “Colonel”

The Rough Riders were his most famous command, so the shorter title stuck in public memory even though his highest rank was lieutenant colonel.