Lewis is the son of Hara and Mark Lewis, who are acting teachers.
In May 2015, Lewis was among the six actors who screen tested for the lead role (which went to Tom Holland) in the 2017 reboot film Spider-Man: Homecoming.
In 2015, Lewis played a supporting role in the comedy-drama film Demolition, starring Jake Gyllenhaal.
He also played in the action thriller remake Point Break, appearing briefly as the young version of the lead character Johnny Utah.
In 2015, Lewis filmed the role of a boy hunted by his babysitter in the comedy horror film The Babysitter, alongside Samara Weaving. The finished film was acquired by Netflix in December 2016 and was released on October 13, 2017, which fell on a Friday.
In 2018, Lewis co-starred in the Canadian horror mystery film Summer of 84. Lewis played a supporting role in the Netflix family film The Christmas Chronicles, starring Kurt Russell.
In 2019, he co-starred in the thriller film I See You, alongside Helen Hunt.
In 2020, he reprised his main role in the comedy horror sequel film The Babysitter: Killer Queen, on Netflix. He also reprised his role as Teddy in the sequel film The Christmas Chronicles 2.