is an Australian actor. He is best known for his roles as Dewey Crowe on the FX neo-western crime series Justified (2010–15), and Romeo on the Starz drama miniseries Flesh and Bone (2015). He is also known for having played Charles Manson twice, first on the second season of the Netflix psychological crime thriller series Mindhunter, and later in the comedy drama film Once Upon a Time in Hollywood (both 2019).

Herriman won the AACTA Award for Best Actor in a Leading Role for his role as Punch in the black comedy film Judy and Punch (2019), and was nominated for the AACTA Award for Best Actor in a Supporting Role for his role as Ruse in the historical psychological thriller film The Nightingale (2018).