He ruled the Moon with a hard-cheese fist and forced all his cheese subjects to pay an unreasonable cracker tax (crackers being their world's currency) and would torture any subject that failed to pay by boiling them in hot mustard.
After Popeye, Olive and Wimpy land on the moon in an experimental rocket, they are captured by Krentz, the Limburger captain of the guard, who takes them to the Big Cheese's castle. Upon their arrival, the king pretends to sympathize with them but quickly betrays them and makes them his prisoners indefinitely. While locked up, they witness the king's cruelty and Popeye decides to stage a coup, breaking out of prison to face the king. The Big Cheese has the upper hand at first, but is swiftly defeated once Popeye eats his spinach, proceeding to punch the king into bits of cheese which run away in terror. With the Moon finally free from the evil king's reign, the cheese people thank Popeye and his friends by refueling their ship and giving them abundant cheese.