Upon graduating from the prestigious National Institute of Dramatic Art (NIDA) in 2008, Alex starred in the independent Australian feature film Wasted On The Young, which garnered much attention at Toronto International Film Festival and South by Southwest Film Festival. This was followed with roles in several independent and studio films in both the US and Australia.

In 2012 Alex played the lead role in the US science fiction thriller Chronicle, which grossed over $126 million worldwide. Following the success of Chronicle, Alex starred in the 2013 re-make of the infamous supernatural horror classic Carrie alongside Julianne Moore and Chloe Grace Moretz followed by a performance in Andrew Niccol's The Host. Alex followed this with starring roles in Australian drama Cut Snake with director Tony Ayres and co-starring Sullivan Stapleton and Jessica Gouw and as Pete Zamperini alongside Jack O'Connell and Jai Courtney in Angelina Jolie's Academy Award nominated epic Unbroken.

Most recently, Alex has starred in Ivan Sen's Australian outback western Goldstone opposite Jacki Weaver and David Wenham; Christian Papierniak's Izzy Gets The F*ck Across Town opposite Mackenzie Davis; Greg McLean's Jungle opposite Daniel Radcliffe for Arclight films; Joseph Kosinski's Only The Brave opposite Miles Teller and Josh Brolin for Sony Pictures, Black Label Media and producer Lorenzo DiBonaventura and Luke Shanahan's Rabbit opposite Adelaide Clemens.

In the summer of 2017, Alex wrapped his most recent project, independent feature Brampyon's Own for writer/director Michael Doneger starring alongside Rose McIver and Jean Smart.

Alex stars as Jim Street in SWAT for CBS Studios and Sony Pictures Television Studios, airing on CBS in 2017.

Alex is represented by UTA, Mosaic and United Management.