In 2021, Smit-McPhee starred in Jane Campion's film The Power of the Dog. The film premiered at the 78th Venice International Film Festival, where it opened to critical acclaim. Smit-McPhee's performance in particular received praise, with Carlos Aguilar of TheWrap calling him "terrifyingly remarkable" and Peter Bradshaw of The Guardian writing, "Smit-McPhee brings something inscrutably complex and reserved to his character's behaviour". In March 2022, Smit-McPhee joined Alfonso Cuaron's upcoming Apple+ series Disclaimer.
