Atanarjuat was cast entirely with Inuit actors from Igloolik.
The cast were a mix of experienced and newly-initiated actors. Natar Ungalaaq as Atanarjuat, and Paul and Mary Qulitalik as Qulitaliq and Nuriuniq, for example, have previous credits in Claude Masson's Kabloonak, CBC's Trial at Fortitude Bay and Turner Broadcasting's Glory and Honor.
Others such as Micheline and Samuelie Ammaq, have ten years of experience in earlier Isuma dramas, such as Qaggiq, Nunaqpa, Saputi, and the nationally-televised 13-part Nunavut series.
Finally, for several principal cast members, such as Sylvia Ivalu (Atuat) and Lucy Tulugarjuk (Puja), Atanarjuat represented their first professional acting experience. Unlike other Isuma productions, in which actors were given a general storyline by director Zacharias Kunuk and then improvised action and dialogue, Atanarjuat required the actors to learn and work from a script.