In 2013, Smit-McPhee filmed the action science fiction film "Young Ones". The film premiered at the Sundance Film Festival in January 2014. Soon afterwards he appeared in "Slow West", which was released in 2015. In March 2014, he was cast in the Nine Network's seven-part drama series "Gallipoli;" which was broadcast in February and March 2015, the year that marks the 100th anniversary of the Gallipoli landing. He plays 17-year-old Thomas "Tolly" Johnson, who ages himself up so that he can enlist with his brother Bevan and ends up fighting at Gallipoli in the campaign that helped create the Anzac legend. The series was produced by Endemol Australia and was shot over a three-month period starting in March 2014. Smit-McPhee played Nightcrawler in "" (2016), a character whose older version was previously played by Alan Cumming. Smit-McPhee reprised the role in "Dark Phoenix", which was released in 2019.