The Malcolm in the Middle family’s last name, surname or family name is Wilkerson.
The surname of the family was meant to be a secret, but Francis’s name tag clearly states “Wilkerson”. On the set, however, a comman cast joke was that the surname was “Nolastname”. “Nolastname” was used in the final episode (Graduation) on a new name tag for Francis.
There was also a joke that appeared in the original pilot script. In that script, Malcolm was walking to school when a neighborhood kid came running up shouting, “Malcolm, Malcolm, Malcolm. I was talking to my parents last night – I was listening to them talk, and what’s your last name?” “Wilkerson, why?” Malcolm replied. “Oh. Who are the Pariahs?” said the other kid. The joke was eventually cut, and the show’s writers subsequently decided never to reveal the family’s last name, but forgot about Francis’s name tag.
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