Born in New York, Greenblatt’s gateway into acting was dance. Living in Florida at the time, she was a competitive dancer when she decided to go for the titular role in Matilda: The Musical. “I wanted to do it 'cause it was my favourite movie,” she recalls. “And I was like, whoa. I could be here on stage and dance and sing and act, all that. And I was like, that's fun.” She missed out on the role but on a subsequent family holiday to LA was asked to take meetings about three different roles. “I didn't even realise the meetings were actually auditions,” Greenblatt remembers. “I obviously had never auditioned for anything in my life. I booked all three of those roles and I was like, what the hell do we do now? Like, I have to do them… that's how it works.”

Two of those roles were guest star spots, and the third was lead in Disney sitcom, Stuck in the Middle. Greenblatt starred as the youngest of seven children, the spritely Daphne Diaz, opposite Jenna Ortega. Her parents moved across the country so that she could take the job and, as she tells it, the rest is history. “That's kind of how my life just changed,” Greenblatt says matter-of-factly. “I never wanted to stop.” From there, she landed roles in blockbusters — Avengers: Infinity War in 2018, In the Heights in 2021 and then, just casually, the biggest movie of 2023, Barbie. Greenblatt played America Ferriera’s unbothered and unimpressed daughter, Sasha. “I always say I never knew how big it was gonna be in the moment while filming, so it kind of just felt like a play date every day,” she explains. Though in saying that, she wasn’t totally immune from having surreal moments with costars like Margot Robbie. “I kept complimenting her teeth 'cause I was like, why do you have the perfect smile? I hate my teeth.” Greenblatt remembers. “And she was like, never touch your teeth. I love your teeth so much. I was like, okay. Awesome.”

This dynamic — Greenblatt as the precocious younger sibling, on set with people much older than her — has been a recurring theme for much of her career. She says she gets on with people older than her by virtue of being surrounded by adults most of the time. “It's so funny, I made a joke the other day. All the teen actors are friends and I'm out of the group,” she says. “I guess it's because a lot of them work with each other and I've only done movies with adults. So they just put me in that group. But I like normal people, they make me happy and they're most like me. Like, I feel like all the other teen actors I've interacted with, I'm like, what is going on inside your head? It's so odd to me.”

Her latest film, Borderlands, saw Greenblatt working with veterans like Cate Blanchett, Jamie-Lee Curtis, Jack Black and Kevin Hart. A film adaptation of the popular video game, Greenblatt stars as Tiny Tina, the “feral pre-teen demolitionist,” who is rambunctious and unruly. “Tina’s the most fun character I've ever played,” she says, explaining that she would work with director Eli Roth to improvise moments and not tell any of the other actors. “I was extremely feral. I mean, I would just like throw food at people and myself and I'd rub it in my hair and I would say the most random shit. And I would do cartwheels and jump on people. I was literally like a rabid animal; they definitely toned it down for the final edit.” Filming took place back in 2021 in Budapest and meant Greenblatt had to miss her middle school graduation. So the cast and crew threw her a surprise one instead, complete with speeches from Curtis, stunt doubles and a (loving) heckling from Hart. “They decorated my cap and gown and they played the graduation song through the speakers of the sound stage,” she recalls. “And they had Cate's stunt double on wires. It was perfect. I had so much fun.”

When I ask if there’s been a moment where she’s stopped and thought about trading in Hollywood for a more average high school life, Greenblatt says it hasn’t occurred to her. “I mean, because I'm always the one that's pushing myself and everyone around me is there to support me and make sure I'm happy,” she explains. “I've never really had to have the conversation of like, I don't wanna do this, I wanna be a normal kid 'cause I'm always the one that wants to keep doing it. I am still learning the balance between a kind-of normal social life and my work life. I'm figuring that out. I'm finding the key. But I do think that going to a normal school and having friends that aren't in the industry, but still understand my perspective and what I do, is really refreshing and nice. I think my parents, my family and my team, they can tell when I get burnt out and they're like, all right girl.”

So just like other teenagers, it’s all a work in progress for Greenblatt. But she’s already figured out that she wants to try her hand at writing, producing and maybe even directing one day. “I mean, there's a lot of stories I wanna tell,” she explains. “I think a couple years ago I was kind of just thinking that whatever role comes my way is what's meant to be. But I think because I’m a teenage girl and I’m receiving these scripts written about a teenage girl that are so inaccurate and dumb, I feel inspired to create my own and to be the voice for people my age because I have the voice and platform.”

Borderlands is out now.