She co-starred as Alicia Clark on the horror drama series Fear the Walking Dead (2015–2023), and made her directorial debut with the seventh season episode "Ofelia".

In 2010, in partnership with the Berlin Philharmonic, Debnam-Carey and around 40 other musicians composed a piece in a two-week program and performed it at the Sydney Opera House.

She appeared in Next Stop Hollywood (2013), a six-part documentary that followed six Australian actors as they competed for roles during the U.S. TV pilot season.

[30] On 1 December 2014, the four lead roles of AMC's Fear the Walking Dead were announced, with Debnam-Carey as Alicia Clark.

[14] At San Diego Comic-Con in July 2015, The 100's showrunner Jason Rothenberg announced that Debnam-Carey would be returning to the show's third season.

[39][40] Considered a breakout star of Fear the Walking Dead as well,[41][42] she also received critical praise for her work in the series, with Erik Kain of Forbes writing, "Debnam-Carey is a fantastic actor.

[45] Debnam-Carey appeared in the lead role of Laura in the German thriller Friend Request, released in Germany on 7 January 2016.

[46] In October 2017, she was cast in the crime drama A Violent Separation (2019) as Frances Campbell, younger sister of the victim.

In 2017 and 2018, she was nominated for the Saturn Awards for Best Performance by a Younger Actor in a Television Series for her work in Fear the Walking Dead.

[54] Debnam-Carey starred as Emily in the eight-part Hulu series Saint X, a psychological drama told through multiple timelines and perspectives, based on Alexis Schaitkin's novel of the same name.

[61] She co-starred in the limited drama series Apple Cider Vinegar, created by Samantha Strauss for Netflix, based on the real-life story of health and wellness scammers.