Margot Robbie Harleen Quinzel / Harley Quinn Ewan McGregor Roman Sionis / Black Mask Mary Elizabeth Winstead Helena Bertinelli / Huntress Jurnee Smollett Dinah Lance / Black Canary Rosie Perez Detective Renee Montoya Chris Messina Victor Zsasz Ella Jay Basco Cassandra Cain Ali Wong Ellen Yee Matthew Willig Happy Dana Lee Doc Steven Williams Patrick Erickson Robert Catrini Stefano Galante Daniel Bernhardt Sionis' Chauffeur François Chau Mr. Keo Miyuki Matsunaga Mrs. Keo Anna Mikami Miss Keo Paul Lasa Franco Bertinelli Charlene Amoia Maria Bertinelli Ella Mika Young Helena Bertinelli Derek Wilson Tim Evans Bojana Novaković Erika Andy Hoff Erika's Date Bruno Oliver Sal Michael Masini Officer Dargo Judy Kain Bespectacled Secretary David Bianchi Henchman Rj Wayne Tough Guy Eddie Alfano Helena's Bodyguard Simon Rhee Cell Guard Sala Baker Prisoner Zack Whyel Roman's Healer (uncredited) Ellay Watson Roller Derby Fan (uncredited) Anthony Molinari Mafiosi (uncredited) Ego Mikitas Don (uncredited) William Guirola Thug (uncredited) Nico Greetham Young Goon (uncredited) Shad Gaspard Lords Leader (uncredited) Eddie J. Fernandez Gauntlet Cop (uncredited) Mike Ferguson Lord of the Avenue (uncredited) Gerald Downey Judge (uncredited) Richard King Mercedes Gang Dennis Keiffer Mercenary Efka Kvaraciejus Mercenary Kofi Yiadom Mercenary Caleb Spillyards Prisoner Terrence Julien Cell Guard Tim Sitarz Donut Cop Buddy Sosthand Coffee Cup Cop Joe Bucaro III Carlos Rossi Pramod Kumar Irate Shopkeeper