- He was the first villain to appear in the series.
- Romeo knows about the PJ Masks' secret identities.
- Romeo was more focused in "Romeo's Disguise".
- Romeo broke the fourth wall by talking to the viewers in "Lionel-Saurus".
- Romeo has been seen twice without his goggles. First in "Owlette and the Flash Flip Trip" on book covers, and again in "Gekko and the Mighty Moon Problem".
- The white streak in his hair could be a reference to Cruella De Vil, the villain from the 101 Dalmatians series who also has black and white hair.
- He sided with Night Ninja and the Ninjalinos in "Catboy and the Shrinker".
- In "Gekko and the Mayhem at the Museum", he revealed that he likes Double Tofu Pistachio ice cream.
- In "Speak UP, Gekko!", there was a brief animation error that removed his legs.
- He is currently the first and only villain in the series with one clear motive: to take over the world. Night Ninja's motives vary, but mostly tie in to proving his "supremacy" and Luna Girl usually just steals things and just plays with them, with no clear motives.
- He calls Catboy "Kitty Litter Boy" more than Luna Girl and Night Ninja, who only called him this once. This could mean that he dislikes Catboy more than the other two, or it could simply be a coincidence.
- Romeo has called the PJ Masks these names:
- PJ Pests, PJ Monkeys, PJ Stinks, Super Stumblers, PJ Pains, PJ Dodos, Daytime Dodos, PJ Do-Gooders, Non-Speaking Ninnies, PJ Show-offs
- Catboy: PJ Pussycat, Kitty Litter Boy, Kitty Cat, Kooky Cat, Pussycat, Biker Boy, Little Kitty
- Owlette: Feather-Brain, Bird-Brain, Birdy
- Gekko: Lizard-Legs, Lizard Boy, Lizardy Loser, Loopy Lizard, Sticky-fingered Stinkeroo
- In "Catboy's Cuddly", it is revealed that he has a cuddly bear named Hugsie Bear.