He is best known for his role as Indigenous teenager Bear Smallhill in the FX on Hulu comedy-drama series Reservation Dogs (2021–2023),[1][2] for which he received several accolades, including a nomination for a Primetime Emmy Award for Outstanding Lead Actor.

[9] Woon-A-Tai starred as Bear Smallhill in the 2021 FX on Hulu comedy-drama Reservation Dogs, "a slice-of-life triumph" from Sterlin Harjo and Taika Waititi.

[2] Set and filmed in rural Oklahoma, Reservation Dogs is a coming-of-age story that follows the antics of rebellious teenagers living on tribal land.

The series' entire creative team, core cast, and crew consists of Indigenous people, with the addition of a few non-Native actors in supporting or guest roles.

The red is supposed to represent violence and blood.” In 2022, it was announced that Woon-A-Tai would be joining Finn Wolfhard and Billy Bryk in the duo's directorial debut Hell of a Summer, which was released in 2023.

In September 2024, it was announced that Woon-A-Tai would be joining Darren Aronofsky's Caught Stealing alongside Bad Bunny, Zoe Kravitz, Austin Butler, Regina King, and Matt Smith.