| Jessica Biel | Cora Tannetti |
| Christopher Abbott | Mason Tannetti |
| Dohn Norwood | Dan Leroy |
| Abby Miller | Caitlin Sullivan |
| Bill Pullman | Harry Ambrose |
| Kathryn Erbe | Fay Ambrose |
| Jacob Pitts | J.D. |
| Rebecca Wisocky | Margaret Lacey |
| Enid Graham | Elizabeth Lacey |
| C.J. Wilson | William
(as CJ Wilson) |
| Patti D'Arbanville | Lorna Tannetti |
| Orlagh Cassidy | Elsa Belmont |
| Christopher Innvar | Frankie's Dad |
| Susan Pourfar | Cora's Public Defender |
| Joseph Melendez | District Attorney Lopez |
| Peggy Gormley | Judge Barrett |
| Meredith Holzman | Sharon |
| Danielle Burgess | Maddie |
| Augie Murphy | Cora (13 y.o.) |
| Rileigh McDonald | Phoebe (9 y.o.) |
| Mia Katigbak | Dr. Tammy Chang |
| Robert G. McKay | Warden Jenkins
(as Robert McKay) |
| Arthur French | Caleb Walker |
| Spenser Granese | Shawn
(as Spencer Granese) |
| Ezra Barnes | Dmitri |
| Kate Levy | Sara |
| Grayson Eddey | Laine Tannetti |
| Colin Hanlon | Danny |
| Adrienne Lovette | Cora's Cellmate |
| Joel Van Liew | Psychiatrist #1 |
| Kristen Adele | Psychiatrist #2 |
| Jacob Berger | Bailiff |
| Takako Haywood | Clerical Worker
(uncredited) |