According to Mario’s newly updated, official Japanese-language profile, the iconic Mario isn’t working as a plumber. This shouldn’t be a total surprise, because the character seems to do everything but plumbing. (and no aerantly war pipes dont count.)
Here is how the recently uploaded Mario profile explains the character:
All around sporty, whether it’s tennis or baseball, soccer or car racing, he [Mario] does everything cool. As a matter of fact, he also seems to have worked as a plumber a long time ago…
According to Shigeru Miyamoto, Mario hasn’t always been a plumber. The character, then named “Jumpman,” was “basically a carpenter” in 1981’s Donkey Kong, as the game takes place on a construction site.
“With (1983’s) Mario Bros., we brought in Luigi and a lot of the game was played underground so we made him to fit that setting and, we decided he could be a plumber,” Miyamoto previously told USA Today. “The scenario dictates his role.”