‘Lessons in Chemistry’ Showrunner Explains How Casting Aja Naomi King as Harriet Made the Show Better

As with any television adaptation of a beloved book, Apple TV+‘s Lessons in Chemistry swerves away from its source material in many minute ways. Fans of Bonnie Garmus’s bestselling novel can nitpick the way heroine Elizabeth Zott (Brie Larson) wears her hair down or how the show slightly changes the backstory for why she names her dog Six Thirty. However, there’s one major change from the book that might leave some readers fully blown away: instead of Elizabeth’s friend and neighbor Harriet Sloane being an unhappily married, older white woman happy to help our protagonist out, the show’s version of Harriet (Aja Naomi King) is a brilliant Black attorney fighting for the future of her neighborhood while ruling over a picture perfect American family.

In fact, in the show, we get to know Harriet far more and far earlier than we do in the book thanks to the fact that she and her children are close friends to Calvin Evans (Lewis Pullman). Rather than emerging as Elizabeth’s support system mid-way through the story, Harriet seems to be the star of her own distinct series about the fight to keep corrupt, racist politicians from building highways through Black neighborhoods. Because of this, the scope of Lessons in Chemistry‘s inherently political storyline expands past the concerns of white feminism epitomized by Elizabeth.

But what inspired this seismic shift to Harriet’s character? Lessons in Chemistry showrunner Lee Eisenberg told Decider that this new version of Harriet came about when they discovered Aja Naomi King was interested in being on the show. King had been up for a different role in Lessons in Chemistry, but the role of Harriet had not yet been cast, leading Eisenberg to wonder..

“I started thinking about, well, what if Aja Naomi King was Harriet? And what do we lose and what do we gain from that?” Eisenberg said. “The story of the show is so much about a woman pushing up against a patriarchal system, a sexist system in a male-dominated field like science. Then to see a parallel story where it’s a Black woman who is contending with all the things that Elizabeth is contending with, but then you add another layer to it of race. What is that like? And how will these women come together and how will they challenge one another?”

“This kind of unlikely friendship became very compelling to me. And one of the first conversations that I had with Bonnie Garmus was pitching that change and she was incredibly receptive to it.”

Since Harriet was now Black and a resident of Sugar Hill, Eisenberg had to dig into the history of that neighborhood and he was horrified when he learned about how the freeway was purposely zoned through Black neighborhoods to ruin the vibrant, successful communities that had been built.

“There would be all these hearings that inevitably would always go through these Black neighborhoods and the neighborhood that Harriet lived in, that Calvin lived in, that Elizabeth moves into, was filled with doctors and lawyers and celebrities. You know, some of the biggest Black personalities at that time. Even still this vibrant neighborhood was completely decimated by this decision,” Eisenberg said.

“As Elizabeth is starting to gain traction [as a feminist TV host in the late ’50s] and, and maybe making some some inroads for her audience, you still see that there are marginalized communities that aren’t afforded the same opportunities.”

This change, as fans will see later on, recasts Elizabeth’s actions against the larger struggle for equality that would soon take over the country as the Civil Rights Movement.

The first two episodes of Lessons in Chemistry are now streaming on Apple TV+.