He has also appeared in the films Rails & Ties (2007), The Stanford Prison Experiment (2015), Nerve (2016), and Love, Simon (2018).

[3] His family moved to Los Angeles to support his acting career full time when he was ten years old.

That same year, he had a recurring role as Joshua Lipnicki on the NBC medical drama television series ER.

In 2010, he was cast as Drew Holt, the son of Lauren Graham's character, on the NBC drama series Parenthood.

In 2016, Heizer starred as Tommy Mancuso in the film Nerve, and from 2017 to 2020, he played Alex Standall in the Netflix original series 13 Reasons Why.