Little has been said about Captain Sweatpants, but his real name is unknown and he can be seen in the comic book store in most of his appearances. Another time he's mentioned is that he attended Stuart Bloom's art gallery showing, as well as participating in the Mystic Warlords of Ka'a tournament at the comic book store. His nickname, Capt. Sweatpants, comes from the fact that he always wears sweatpants with a superhero t-shirt. He is portrayed by Ian Scott Rudolph who has didn't have a credit for any appearance in the role until "The Occupation Recalibration" (S7E13). He also appears to be a friend of Wil Wheaton when they went to see the movie Raiders of the Lost Ark. He is also on Stuart's bowling team.
He was most recently seen at a high end comic book shop called Capital Comics owned by Jessie (played by Josh Peck), a rival of Stuart's who looks down upon Stuart and his business. Stuart confronts him about not being in his store. Apparently he went to Capitol Comics for the popcorn. Also, this is the first time in the whole series that Captain Sweatpants ever has a line to speak - "Free popcorn".
- The Hofstadter Isotope (S02E20)
- The Creepy Candy Coating Corollary (S03E05)
- The Excelsior Acquisition (S03E16)
- The Wheaton Recurrence (S03E19)
- The 21-Second Excitation (S04E08)
- The Justice League Recombination (S04E11)
- The Russian Rocket Reaction (S05E05)
- The Stag Convergence (S05E22)
- The Bakersfield Expedition (S06E13)
- The Occupation Recalibration (S07E13)