[8] In 2017, he gained wider recognition for playing John Paul Getty III in Ridley Scott's thriller All the Money in the World[9] and a troubled teenager in Andrew Haigh's drama Lean on Pete.

[15] Plummer eventually transferred to and attended the Professional Children's School in Manhattan due to his demanding filming schedule on television shows.

[8] In 2012, Plummer made his feature film debut by playing a supporting role in David Chase's drama Not Fade Away.

[19] In 2013, Plummer joined the BYUtv's drama series Granite Flats, in which he played the lead role of Timmy Sanders.

He played the kidnapped heir John Paul Getty III in Ridley Scott's crime thriller All the Money in the World.

[25] The same year, Plummer portrayed the troubled teenager Charley who finds solace and purpose in his friendship with the titular racehorse in Andrew Haigh's drama Lean on Pete.

[10] The actor felt a deep desire to play the role after connecting strongly with the story, which spurred him to send a letter to Haigh, expressing his passion for the project.

[36] In the same year, Plummer also had a leading role in Hulu's serial adaptation of John Green's novel Looking for Alaska, starring as 16-year-old Miles "Pudge" Halter.

[37][38][39] In 2020, Plummer starred in Thor Freudenthal's drama Words on Bathroom Walls, playing a young man diagnosed with schizophrenia, and headlined the dark comedy Spontaneous, directed by Brian Duffield and based on the novel of the same name by Aaron Starmer.