A Meta Casting after the series ended: Keiko Kitagawa appeared in The Fast and the Furious Tokyo Drift as the character Reiko in 2006. Later that same year, Ayaka Komatsu starred in Japan-only movies Drift and Drift 2 with a character named Mina.
Contest Winner Cameo: The PGSM campaign winners during the series' first half were the live audience for the Kirari Super Live concert.
Creator Cameo: Usagi's father Kenji Tsukino in the Special Act was played by veteran Toku director Ryuta Tasaki (who directed the first 2 episodes). The wedding guests were played by the show's staff as well.
Executive Meddling: Wonder why the ending feels a little rushed? The series was supposed to go a full 52 episodes plus the specials. The ratings led the network to chop the episode order down to 49 episodes late in production.
Mamoru is commonly called "Tuxedo Kamen Rider" by the fandom in a reference to both this show and Kamen Rider Hibiki (Jouji Shibue playing Ibiki in that show).
Dark Mercury is also called "Darkury" by fans. A lesser-used name for her civilian form is "Akumi", combining the word for "evil" (whose kanji may be read "aku") and Ami. Rumor has it this name was coined by the show's staff.
In an episode where Usagi went missing and Ami had to stand in for her not to get Ikuko-mama worried. Ami went so far as to replicate Usagi's hairstyle. And so fandom started calling her "Usami".
Star-Making Role: Keiko Kitagawa as Sailor Mars. This was her acting debut, which led directly to her career in film. It probably helped that, of the Sailor Senshi, most of the fandom agreed she was the best match for her character. While the other cast members are in different fields, Keiko is still the one most widely known.