Junior first appeared in Whiz Comics #25 (December 1941) in Part One of a three-issue crossover with Master Comics. There, he crosses swords with Hitler's super
(Elvis Presley was a big Captain Marvel, Jr. fan. He styled his hair as well as some of his costumes on the young superhero. Unlike Elvis, Junior did not gain weight or abuse substances or die young. I believe he's currently a blond he's somewhere in the DC universe.)
Captain Marvel, Jr. is approaching his 75th birthday, lasting (I'm sure) far longer than creators Ed Herron and Mac Raboy ever thought.
In this issue he meets Professor Werewolf, travels west to meet the Outlaw of Crooked Creek, faces crime's trumpeter, and delves into the mystery of the hammer that shook the world.