First appearance: New Fun Comics #6 (October 1935)
<Yes, before Superman came on the scene!>

Dr. Occult would be in one-page features for four issues of New Fun Comics (which changed its name to "More Fun Comics" in the following issue) before increasing in length to two pages per an issue for a while.
By the end of his run, Dr. Occult's regular feature would be four pages long!

And from Who's Who: The Definitive Directory of the DC Universe Vol. VI (August 1985):