At Saturday's New York Comic-Con panel, Cudlitz surprised attendees by cursing out the producers and cast from the audience before the casting news was announced.
The Walking Dead: More details on the new season
Cudlitz (Southland) will play Abraham, a sergeant who becomes Rick's right hand man in the comics.
Retired at 35 vet McDermitt will play Eugene, a former science teacher.
The Walking Dead returns Sunday at 9/8 on AMC.