‘Hal & Harper’ Creator Cooper Raiff Says Lili Reinhart Was “The Very First Person” He Thought Of to Play Harper

When writing Hal & Harper, Cooper Raiff always envisioned himself as half of the show’s titular siblings, something he admitted has “never been the case” with any other project he’s written.

“I just knew that I was Hal,” he explained to DECIDER over Zoom last month. “I don’t know why, but I felt really called to play Hal, and I knew he was going to be a college senior. So that’s why I needed to make it right away, because I knew I was going to get too old for that.”

The same went for Lili Reinhart, who Raiff said was “the very first person” he thought of to play Harper.

“Harper lived in my heart and brain for probably five years before I started thinking about actually having to cast her,” he recalled. “And the only way to cast her was just to find, not like, who’s the most like Harper, but just like, who is deep. Who has depth and who do I want to follow into the dark tunnel and exploring one’s self and one’s pain and trauma. I fell in love with Lili, all of her work and her interviews and I just knew that she was Harper.”

The series, which centers on the two siblings and their father (Mark Ruffalo) following the loss of their mother, uniquely features Raiff and Reinhart playing their seven and nine-year-old selves among real-life elementary school-aged children in flashbacks. While Reinhart noted that “the whole show” revolves around them “tapping into that seven and nine-year-old versions of themselves and informing the audience why they are the way that they are now that they’re adults,” she admitted that the experience was “definitely out of [her] comfort zone.”

“I’m not bad with kids. I just am awkward with them,” she shared. And I think they were also confused as to why I was around them.”

She ultimately teased, “Thank God Harper wasn’t this social butterfly as a nine year old, because I would not know how to chat up these kids right now or have it seem organic.”

“The fact that she kept to herself and felt uncomfortable and like she didn’t belong with her peers really helped me in terms of being a grown woman around nine year olds. Not to say it wasn’t super entertaining and fun. It was fun. But I always had a little bit of anxiety when we had to shoot those scenes with children, because I felt just very awkward in my own body.”

Raiff, for his part, recalled the experience as “fun” and “funny,” sharing how the show’s casting director, David Rubin, “was sending a lot of tapes in the beginning of these really talented young actors.” However, that wasn’t necessarily what Raiff had envisioned.

“I was like, are there any  tapes of kids that are younger? And he was like, yeah, but there’s not much going on in those tapes. And I was like, send me those,” he said. “And when I had watched some of them, I was like, that’s the show.”

He likened the show to “a real six year old who is just on a different planet,” and highlighted how “you see the ways in which Hal and Harper grew up too fast,” such as in the scene where their father takes them to an amusement park called Adventure Landing.

“Hal is very much acting like a seven year old, but he’s attuned in a way or anxious in a way, or constantly scanning in a way that the other six year olds are just not,” he elaborated. “They’re not desperate to connect. They just want to go to have fun at Six Flags with their brother and with their friends and it’s this really sad, in a lot of ways, thing. But I love watching them try to be kids, and I love how desperate Hal is to have fun at the Adventure Landing, and how hard it is for Harper to have fun and watching her finally get some of that kid-like joy.”

Another choice that further emphasizes the show’s focus on Hal and Harper was the fact that Ruffalo’s character is never referred to by name, only as Dad by his two kids. Raiff described Ruffalo’s character as “this dad grappling with needing, or for some reason wanting to just dedicate his life to just being dad, when in the present, he is just dealing with the fact that he wasn’t a dad for so long and that went in the past and that timeline in the past.”

“I think he kind of wakes up and tries to go to his children where they are,” he continued. “But I think by the end in that timeline, he realizes that that’s not being a dad either. And, I think still in his present, he’s grappling with how to be a dad. But the show is called Hal & Harper and he’s consumed by Hal and Harper, so much so that he’s having trouble starting to have this new experience with Kate and having a new baby come along. It’s bringing up so much, but hopefully he can. Like, if there was a Season two, we hopefully wouldn’t just refer to him as Dad.”

But will there be a Season 2? While Raiff told Deadline in January that he had already planned out more seasons for Hal & Harper, he told DECIDER where he sees the series’ sibling duo going forward.

“I think Harper, I think she’s going to find what she’s looking for in London,” he explained of Reinhart’s character, who lands a job in London. “And I think Hal is going to get what he needs wherever he goes. And I think they’re going to spend a lot of time apart and growing.”

“Season 2 feels like it would be pretty boring,” he teased. “So I think that one season’s good.”

“They’re healed!” Reinhart quipped.

Hal & Harper Season 1 is streaming on MUBI.