| Margot Robbie | .... | Harley Quinn |
| Rosie Perez | .... | Renee Montoya |
| Mary Elizabeth Winstead | .... | Helena Bertinelli |
| Mary Elizabeth Winstead | .... | The Huntress |
| Jurnee Smollett-Bell | .... | Dinah Lance |
| Jurnee Smollett-Bell | .... | Black Canary |
| Ewan McGregor | .... | Roman Sionis |
| Ella Jay Basco | .... | Cassandra Cain |
| Chris Messina | .... | Victor Zsasz |
| Ali Wong | .... | Ellen Yee |
| David Ury | .... | Sleazy Breeder |
| Sara Montez | .... | Shallow Friend #1 |
| Sara Montez | .... | Kathrine |
| Isabel Pakzad | .... | Shallow Friend #2 |
| Daniel Bernhardt | .... | Sionis' Chauffeur |
| KC Strubbe | .... | Naïve Teammate |
| Jacky Shu | .... | Skeptical Teammate |
| Paloma Rabinov | .... | Bitchy Teammate |
| Derek Wilson | .... | Detective Tim Monroe |
| Guiseppe Bucaro | .... | Carlo Rossi |
| James Henry Williams Jr. | .... | Ace Chemical Police Officer |
| François Chau | .... | Mr. Keo |
| Miyuki Matsunaga | .... | Mrs. Keo |
| Anna Mikami | .... | Miss Keo (16 yrs) |
| Bruno Oliver | .... | Bodega Cook (Sal) |
| Keisha Tucker | .... | Roller Derby Girl |
| Matthew Willig | .... | Happy |
| Jeremy Denzlinger | .... | Desk Sergeant |
| Michael Masini | .... | Officer Drago |
| Charles Carpenter | .... | Processing Officer |
| Daniel Cole | .... | Patrol Cop |
| Jesse Bush | .... | Patrol Cop |
| Steven Williams | .... | Captain Patrick Erickson |
| Charlene Amoia | .... | Maria Bertinelli |
| Paul Lasa | .... | Helena's Father |
| Ella Mika | .... | Young Helena |
| Robert Catrini | .... | Stefano Galante |
| Eddie Alfano | .... | Helena's Bodyguard |
| Chris Carnel | .... | Desk Sergeant |
| Buddy Sosthand | .... | Coffee Cup Cop |
| Tim Sitarz | .... | Donut Cop |
| Shawn Balentine | .... | Key Card Cop |
| Shahaub Roudbari | .... | Smarmy Guy |
| Pramode Kumar | .... | Irate Shopkeeper |
| Christine Engh | .... | Elderly Woman |
| KK Barrett | .... | Dr. Aguilar |
| David Bianchi | .... | Sionis Henchman #1 |
| Simon Rhee | .... | Cell Guard |
| Terrence Julien | .... | Cell Guard |
| George Crayton | .... | Prisoner |
| Caleb Spillyards | .... | Prisoner |
| Qiang Li | .... | Prisoner |
| Anthony Nanakornpanom | .... | Prisoner |
| Sala Baker | .... | Prisoner |
| Christian Womack | .... | Prisoner |
| Bryan Sloyer | .... | Prisoner |
| Kofi Yiadom | .... | Mercenary |
| Efka Kvaraciejus | .... | Mercenary |
| Sam Hargrave | .... | Mercenary |
| Dennis Kieffer | .... | Mercenary |
| Dana Lee | .... | Doc |
| Bojana Novakovic | .... | Erika |
| Andy Hoff | .... | Erika's Date |
| Eric Michael Cole | .... | Disgruntled Man |
| Oakley Lehman | .... | Mercedes Gang |
| Richard King | .... | Mercedes Gang |
| Tim Rigby | .... | RR Passenger |
| César Alejandro | .... | Market Shopper with Hat (uncredited) |
| David Anthony Buglione | .... | Joe Bertinelli (uncredited) |
| John Carlo Castro | .... | The Joker (uncredited) |
| Jason Catron | .... | Sprang Bridge Soldier (uncredited) |
| Dan Cole | .... | Officer Timm (uncredited) |
| Stephen Corliss | .... | Courtesy Clerk (uncredited) |
| Joey Courteau | .... | Club Dancer (uncredited) |
| Phil DiGennaro | .... | Hunter (uncredited) |
| Sadyr Diouf | .... | Roman's Goon (uncredited) |
| Jack Dourakos | .... | Club Goer (uncredited) |
| Gerald Downey | .... | Judge (uncredited) |
| Michael Edelstein | .... | Pawnbroker (uncredited) |
| Mike Ferguson | .... | Lord of the Avenue (uncredited) |
| Eddie J. Fernandez | .... | Gauntlet Cop (uncredited) |
| Julian Garcia | .... | Roman's Goon (uncredited) |
| Shad Gaspard | .... | Lords Leader (uncredited) |
| Luis Richard Gomez | .... | Harley Super Fan (uncredited) |
| Nico Greetham | .... | Young Goon (uncredited) |
| William Guirola | .... | Thug (uncredited) |
| John Hennigan | .... | Lords Gang Member (uncredited) |
| Damon Hoffman | .... | Bodybuilder (uncredited) |
| Brandon Irvin | .... | Roman's Goon (uncredited) |
| Jesse James | .... | Lords of The Avenue Gang (uncredited) |
| Judy Kain | .... | Bespectacled Secretary (uncredited) |
| Leo Lam | .... | Dancer (uncredited) |
| Arlondriah Lenyéa | .... | Featured Dancing Club Kid (uncredited) |
| Jeff Lipary | .... | BBB Gang Member (uncredited) |
| Di Medio Lucas | .... | Roman's bodyguard (uncredited) |
| Lenora May | .... | Mrs. Marcucci (uncredited) |
| Lawrence Mclendon | .... | Goon (uncredited) |
| Ego Mikitas | .... | Don (uncredited) |
| Cavin Mohrhardt | .... | Roman's Goon (uncredited) |
| Anthony Molinari | .... | Mafiosi (uncredited) |
| Brandon Garic Notch | .... | Roman's lift Goon (uncredited) |
| Adinett Nsabimana | .... | Girl at the bar (uncredited) |
| Brian Nuesi | .... | Husband (uncredited) |
| Matthew Parry-Jones | .... | Club Goer (uncredited) |
| Nick Phillips | .... | Roller Derby Fan (uncredited) |
| Diezel Ramos | .... | Gotham Detective (uncredited) |
| Talon Reid | .... | Roman's Goon (uncredited) |
| Zeus Sagittarius | .... | Roman's Goon (uncredited) |
| Greice Santo | .... | Scantily Clad Crystal (uncredited) |
| Nev Smith | .... | Gotham Detective (uncredited) |
| Dustin Stern-Garcia | .... | Rob Gregorian (uncredited) |
| Karen Teliha | .... | Nun (uncredited) |
| Ellay Watson | .... | Roller Derby Fan (uncredited) |
| Ryan Watson | .... | Prisoner #1 (uncredited) |
| Rj Wayne | .... | Tough Guy (uncredited) |
| Zack Whyel | .... | Roman's Healer (uncredited) |