Frederiksen played minor parts in the television shows Young Lions (2000), Mermaids (2001) and Blue Heelers (2002). He secured his first major television role as part of the cast of Australian series Stingers in its seventh season, playing Leo Flynn. He received a Logie Award nomination in the category of Most Popular New Male Talent for his work on Stingers in 2004. He later played the lead in the ABC telemovie Bastard Boys in 2007, and received an AFI Award nomination as Best Lead Actor for his portrayal of Australian politician Greg Combet. In 2019, Frederiksen was cast in Upright, an Australian TV series created by Chris Taylor. Frederiksen also portrayed Wallow in the 2007 Sony Pictures film Ghost Rider. He starred in the Australian feature film Ten Empty (2009). Other film credits include feature films Summer Coda (2009) and Closed for Winter (2007) and an appearance in Underground. Frederikson also played a trangendered mother in Pawno, which premiered at the Melbourne International Film Festival.