Travis Fimmel Ragnar Lothbrok Actor Gustaf Skarsgård Floki Actor Katheryn Winnick Lagertha Actor Clive Standen Rollo Actor Alexander Ludwig Bjorn Actor Alyssa Sutherland Queen Aslaug Actor Ben Robson Kalf Actor Peter Franzén King Harold Finehair Actor Jasper Pääkkönen Halfdan the Black Actor Dianne Doan Yidu Actor 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