Actually it's 5... he did Chasing Amy as well (assuming that's the one you forgot.) Although very comedic, with an epic speech by Smith, falls into the sap category JG is most likely put into.
He apparently did the Jersey Girl film to break away from the re-occuring 'jersey series' familiarity, which he re-visited with Clerks II. I really did enjoy Carlin's role in this film however.
There was also a film released under View Askew titled 'Vulgar', which has some familiar character features (mewes, o'halloran, etc), but is completely unlike any film on the label. It is an extremely disturbing film I would not recommend to the average viewer, but if twisted is your cup of tea.. worth a visit.