It was called Batman, The Electrical Brain Chapter 1.
Released July 16, 1943...:
http://goldenagebat.blogspot.com/2014/07/batman-chapter-1-july-16-1943.html?m=1
The 1943 Batman serial is often considered a footnote in the 75 year history of the Dark Knight. If it's mentioned, it's usually a short bit that almost invariably goes like this: "first live-action Batman, wartime serial, very cheap, bad costumes, no Batmobile, first Batcave and Alfred, incredibly racist." And while, yes, all those things are true, the serial is far more important than that and deserves some more in depth consideration.
Lewis Wilson starred as Batman, at the ripe old age of 23...:
While he did other movie work Batman is the role he’s best known for. He passed away in 2000 at age 80.