He was a regular character in the strip from the 1950s until the mid-1980s. While not the main character, he frequently appeared alongside Superman and Lois Lane.
It's worth noting that Superboy has also been featured in other comic strips, such as:
* "Superman's Pal, Jimmy Olsen": This strip was a spin-off of "Adventures of Superman" and often featured Superboy as well.
* "The New Adventures of Superman": A more modern rendition of the "Adventures of Superman" comic strip, this one featured Superboy in a few storylines.
So, while "Adventures of Superman" is the most prominent, it's not the only comic strip where Superboy has made an appearance.