After the one-shot comic published in 1946, the Mysterious Traveler disappeared for a decade...
...to reappear in 1956 in a new, ongoing series.
This new series didn't adapt radio show episodes, as the previous one-shot did.
In fact, when the comic debuted, the radio series had been off the air for almost four years!
But the character was still well-known enough that Charlton thought he would be a name-value host for their new "mystery" book as well as being a "safe" character the new Comics Code Authority wouldn't object to.
By the way, the distinctive art for this story was by Spider-Man co-creator Steve Ditko, who would do at least one story or a cover per issue from this tale in #2 to the end of the title's run.