The Phantom is about as old school as you can get for superheroes. In fact, he predates Superman by two years.
In addition to his comic serials spanning over 1600 (?!!) issues, The Phantom has appeared in many other comics. He was even part of the animated superhero team Defenders Of The Earth with Flash Gordon and Mandrake The Magician.
Billy Zane played him in a 1996 theatrical film, back when almost all superhero movies sucked.
Here, courtesy of Archive.org, is the first live action adaption of The Phantom. The complete 15 part 1943 serial for your old-school enjoyment. Grab some popcorn, invite some friends, and check out one of the original superhero movies.