He later studied acting at the University of Southern Queensland, graduating with a Diploma of Creative Arts in 1987, and in his early career worked alongside fellow actor Geoffrey Rush with the Grin and Tonic theatre troupe.

[10][11][12] In 2007 Dykstra was nominated for an AFI Award for Best Supporting Actor for his performance in Romulus, My Father directed by Richard Roxburgh.

Dykstra's theatre credits are extensive, including God of Carnage,[15] The Wonderful World of Dissocia,[16][17] The Unlikely Prospect of Happiness,[18] for the Sydney Theatre Company and Babyteeth,[19][20] Ray’s Tempest, The Underpants, The Laramie Project, Yibiyung and The Ham Funeral for Company B.

[27] In 2016 Dykstra received an AACTA Award Nomination for Best Supporting Actor in a Television Drama for his performance as Barney in season 4 of Rake.

[28] More recently Dykstra portrayed Lester in the Matchbox Pictures production Irreverent streaming on Peacock in the US and Netflix Australia.