During the opening credits, we see a glimpse of Fillmore's permanent record, which shows him classified as a "delinquent." The past offenses listed for him are: chalk boosting, locker rigging, comic book poker ring, class cutting, milk counterfeiting (non-dairy creamer), backtalkery.
All the main characters' last names are street names in San Francisco.
After several years off the air, Disney XD aired a marathon of the series in April 2018.
Released on streaming via Disney+ in the United Kingdom and the Republic of Ireland on July 27, 2022. They are the only 2 countries streaming Fillmore for the first time.
Jazz music and references to it are present throughout the series. Fillmore has named his first goldfish Thelonious after Thelonious Monk and replaces him with Miles (named after Miles Davis) after he dies. In the episode "Of Slain Kings in Checkered Fields", Ingrid Third is listening to a Chet Baker record.