Main •
Edie Falco as
Leslie Abramson, the defense attorney who represented Lyle and Erik Menendez. •
Gus Halper as
Erik Menendez, the younger brother •
Julianne Nicholson as Jill Lansing, Abramson's partner on the defense team for the first trial. •
Constance Marie as Marta Cano, José's sister. •
Carlos Gómez as José Menendez, Lyle and Erik's father. •
Josh Charles as Dr. Jerome Oziel, Lyle and Erik's psychiatrist. •
Sterling Beaumon as Glenn Stevens, Lyle's friend from
Princeton University. •
Ben Winchell as Donovan Goodreau. •
Molly Hagan as Joan Vandermolen, Kitty's older sister. •
Chris Bauer as
Tim Rutten, Leslie's husband and a Los Angeles Times journalist. •
Heather Graham as Judalon Smyth, Oziel's emotionally fragile mistress. •
Elizabeth Reaser as Deputy District Attorney Pam Bozanich, who was assigned to the murders of José and Kitty Menendez. •
Larry Cedar as Milton Andersen, Kitty's older brother. •
Ezra Buzzington as Deputy District Attorney Elliott Alhadeff, first prosecutor in case. •
Raphael Sbarge as Jon Conte. • Taylor Kalupa as Anna Eriksson, Lyle’s fiancé & eventual wife. •
Jenny Cooper as Megan Lang. •
Irene DeBari as Maria Menendez, Lyle and Erik's grandmother.
Guest starring • Douglas Olsson as
Robert Shapiro, Erik's lawyer (prior to Leslie Abramson) who arranged his surrender from Israel.
Cameo appearance • Dominic Daniel as
O. J. Simpson, who is accused of murdering his ex-wife and her friend. He is shown to be jailed beside Erik, but only a voice is present during the conversations. He made an appearance in episode 8 when the news showed his actual verdict. ==Episodes==