[1][2] In 2024, he starred as Billy Maximoff / William Kaplan in the Marvel Cinematic Universe miniseries Agatha All Along and as Tobias Ragg in a Broadway revival of the musical Sweeney Todd: The Demon Barber of Fleet Street.

[9] While in high school, Locke and three fellow students submitted a petition to government officials to investigate the feasibility of welcoming Syrian refugees to the Isle of Man.

[10][11] In 2022, Locke began starring as Charlie Spring in his debut television role in the Netflix coming-of-age series Heartstopper, an adaptation of the webcomic and graphic novel of the same name by Alice Oseman.

[18] In the same year, Locke took on the role of Tobias Ragg in the musical Sweeney Todd: The Demon Barber of Fleet Street on Broadway.

[21][22] In August 2022, Isle of Man Health Minister, Lawrie Hooper announced that the government would change its blanket ban on gay men donating blood after Locke called for the "archaic" rule to be changed in a video message played at the island's annual pride celebration.