The family's surname is never mentioned directly in the series. Linwood Boomer's script for the pilot episode originally included the surname Wilkerson, but it was later removed because he did not want to put "any specific ethnic label on the characters". The surname appeared in early drafts of promotional material and also on Francis's Marlin Academy uniform in the pilot. In the last episode of the series, Francis drops his ID badge from his new office job, which lists his name as "Francis Nolastname". Also in the last episode, the principal announces Malcolm as the speaker, clearly mouthing "Nolastname" as his voice is drowned out by microphone feedback. A publicist for Fox said that "officially the family's last name should be considered a mystery".