Travis Fimmel Ragnar Lothbrok Actor Katheryn Winnick Lagertha Actor Clive Standen Rollo Actor Gustaf Skarsgård Floki Actor Linus Roache King Ecbert Actor Alyssa Sutherland Queen Aslaug Actor Alexander Ludwig Bjorn Actor Ben Robson Kalf Actor Moe Dunford Aethelwulf Actor Lothaire Bluteau Emperor Charles Actor Jasper Pääkkönen Halfdan the Black Actor Kevin Durand Harbard Actor Jennie Jacques Judith Actor Peter Franzén King Harold Finehair Actor Morgane Polański Princess Gisla Actor Amy Bailey Queen Kwenthrith Actor Dianne Doan Yidu Actor John Kavanagh The Seer Actor Josh Donaldson Guest Star Ivan Kaye King Aelle Guest Star Michael Hirst Executive Producer Morgan O'Sullivan Executive Producer John Weber Executive Producer Sherry Marsh Executive Producer Alan Gasmer Executive Producer James Flynn Executive Producer Sheila Hockin Executive Producer