Superman did a lot of weird stuff in the Silver Age (roughly the '50s through the '60s or early '70s). He certainly went undercover a bunch, and I remember at least once where he gave up being Clark Kent and took up a different secret identity. I don't remember offhand what the name was or why, but he wore a blond wig. I'll see if I can find where that happened.
Once in the '60s Clark apparently died (in an explosion, I think?), so he decided to go without a secret identity and moved in with Jimmy. That was a disaster, largely because everyone now knew where he lived, so he figured out a way to bring Clark back without people being suspicious.
