Main protagonist of JoJo no Kimyou na Bouken Part 1: Phantom Blood. His nickname is "JoJo", a name that the leading character of each following Part possesses, in one way or another.
Comes to learn the powerful martial art Hamon under the tutelage of Will Anthonio Zeppeli. Hamon plays a major part in Part 2 as well, utilized by Jonathan's grandson Joseph Joestar and others.
Dio Brando, his surrogate brother-turned-vampire, is his life-long nemesis, causing him hardship and tragedy up to their final battle at the end of Part 1.
His nickname, and the subsequent nicknames of his descendants, are a reference to the Beatles song Get Back.