[4] Sampson's acting career launched in 1996 with the role as Dylan Lewis's sidekick on Recovery,[5] an ABC youth music show.

[5] The following year he played Leonardo da Vinci in the children's television series Time Trackers and Michael Thorneycroft in the three final episodes of Underbelly.

[5] In 2010, Sampson helped his friend and fellow former Recovery presenter[8] Leigh Whannell develop a horror film called Insidious.

In 2022, Sampson played the lead role of Dennis "Cisco" Wojciechowski in the Netflix drama series The Lincoln Lawyer, based on the novel of the same name and written by Michael Connelly.

[11][12] Sampson was an occasional co-host of Australian radio show Get This with Tony Martin on Triple M.[13] Sampson was a founding member of The Forbidden Fruit, an experimental troupe whose only performance was a risque interpretation of Mad Max 2 they performed on late night radio, in which Angus played The Lord Humongous, who turned out to be quite proficient with the jazz flute.