- Actor-Shared Background:
- Kevin Weisman is Jewish, just like Dale Yorkes.
- Ariela Barer (Gert Yorkes) is also of Jewish descent (or rather, specifically, Mexican-Jewish).
- The Minorus are all portrayed by Japanese-American actors.
- Chase Stein may be Jewish, if his surname is any indication. Gregg Sulkin himself is actually Jewish.
- All-Star Cast: The cast has been described as such by Los Angeles Times.
- The Cast Showoff:
- Ariela Barer (Gert) is also a singer-songwriter, and co-wrote the lullaby she sings to Molly in episode two.
- Lyrica Okono (Nico), Brittany Ishibashi (Tina Minoru), and James Yaegashi (Robert Minoru) are all black belts. While they stick to wizardry for most of the fights (likely to avoid the stereotype of All Asians Know Martial Arts), they do get a hand-to-hand fight between Nico and her parents in "Split Up" that showcases the actors' skills.
- Dawson Casting:
- Most of the Runaways (sophomore high school students, placing them in the 15-17 age range) are played by actors in their early-to-mid-twenties, and all of them (save Allegra Acosta as Molly) were past high school age upon the series' releasenote .
- Danielle Campbell (born 1995) as Eiffel and Timothy Granaderos (born 1986note ) as Lucas.
- Development Hell: The movie that would eventually become the TV series was stuck in development for nearly a decade.
- Fake American:
- English actor Gregg Sulkin as Chase Stein. However, after the first season this became averted as Sulkin became an American citizen in May 2018.
- Australian Julian McMahon plays Jonah. While his nationality isn't clear, him being Ambiguously Human and all, he does use an American accent while playing him.
- Ultimately zig-zagged when it's revealed that the original Jonah was Australian, and the Magistrate's American accent took over when he possessed him.
- Irony as She Is Cast: Ariela Barer (Gert Yorkes) came out as gay in December 2017, and she's the only openly LGBT+ member of the cast. Since Karolina and Nico are lesbian and bi, respectively, Gert is the only one of the older girls who's doesn't identify as LGBT+.
- The Other Darrin: Subverted. Tina Minoru was played by Linda Louise Duan in Doctor Strange (2016), but she's played by Britanny Ishibashi here, but they are eventually considered separate characters with the same name... or were, until season 2 implied Tina lived through the events of that movie.
- Real-Life Relative: The actress who plays younger Janet Stein is Sorel Carradine, Ever Carradine's younger first cousin.
- Self-Adaptation: Brian K. Vaughan himself vocally approved all of the changes made for the series. He even pitched some of them himself, having spent a month in the writing room, though he still makes a point that he doesn't run the show.
- What Could Have Been: Originally, Runaways was going to be a full-on MCU movie that got as far as casting calls before they decided to cancel it for being too complicated for audiences to accept (in the comics the plot ropes in time-travellers, mad scientists, aliens, crimelords, witches, mutants and pan-dimensional god-monsters, and that's just the origin). It was retooled in a show after more movies were released to develop the universe, making it easier for audiences to accept.
- You Look Familiar:
Trivia / Runaways (2017)