Obi-Wan Kenobi

In the original Star Wars trilogy, Obi-Wan Kenobi is played by Alec Guiness.

in A New Hope, Obi-Wan is first introduced as old Ben Kenobi, a hermit that rescues Luke Skywalker from a group of Tusken Raiders.  However, it soon revealed that Obi-Wan is a Jedi Knight and he helps train Luke.