[6] Wallis is also known for voicing the character Harper in the animated film Trolls (2016); as well as her role as Kyra in the television sitcom Black-ish (2019).

She was chosen out of 4,000 to play Hushpuppy, an indomitable child prodigy and survivalist who lives with her dying father in the backwoods bayou squalor of Louisiana.

Her reading prowess, loud screaming voice, and ability to burp on command impressed the director and won her the part.

Wallis's performance drew widespread acclaim and Zeitlin won the Caméra d'Or, the festival's award for best first feature film.

[14][15] Wallis is the first African-American child actor and the first person born in the 21st century to earn an Oscar nomination.

[16] For this, she was nominated for the Golden Globe Award for Best Actress in a Motion Picture – Comedy or Musical but the film was panned by critics.