Lillis has also appeared in the HBO psychological thriller miniseries Sharp Objects (2018) and the film Dungeons & Dragons: Honor Among Thieves (2023).

[5] Previously, she had a minor role in Julie Taymor's stage production of William Shakespeare's A Midsummer Night's Dream, which was also filmed for live showings.

Directed by Andy Muschietti, It also starred Jaeden Martell, Finn Wolfhard, Wyatt Oleff, Bill Skarsgård, Jack Dylan Grazer, Jeremy Ray Taylor, and Chosen Jacobs.

[18] Later that same year, she appeared with Paul Bettany in Uncle Frank, an independent film by True Blood and Six Feet Under creator Alan Ball, which premiered on Amazon Prime in November 2020.

[19] Lillis is part of an ensemble cast, including Scarlett Johansson, Jeff Goldblum, and Tom Hanks, who appear in the Wes Anderson film Asteroid City.