ASA Peter Stone
The deputy Chief of the Special Prosecutions Bureau for Cook County in Chicago.
- The Ace: He is a gifted attorney and is noted to be quite young for someone in his position.
- Career-Ending Injury: He was a professional baseball player, and played for the Chicago Cubs, when a torn muscle ended his athletic career.
- Crusading Lawyer: A straightforward, sharp-witted ASA of Chicago who relentlessly pursues justice for the victims of the cases he handles with a passion.Antonio Dawson: "(Stone)'s a straight-shooter, doesn't play politics, fights for the right things."
- The Determinator: Stone is ambitious, determined and takes the cases he's handed to heart, and won't let anything stop him from pursuing justice for the victims and their families.
- Experienced Protagonist: Peter is clearly a veteran, having been practicing law and been an ASA for years.
- In the Blood: He is the son of renowned New York City District Attorney Ben Stone from Law & Order.
- Parental Issues: He's been estranged from his father for some time because of the elder Stone's self-righteousness.Stone: My father? Screw my father! Maybe he can live with one foot in heaven...That's his special purpose in life, you know? To make everyone around him take note of their own imperfections.
- Remember the New Guy?: Stone was the actually the prosecutor who put Detective Voight in prison for his harassing Lieutenant Casey.
- Sharp-Dressed Man: Is a prosecutor for Cook County wearing in a slick suit while in court.
- Spin-Offspring: Turns out he's the son of Law & Order original cast member Benjamin Stone.
SA Mark Jefferies
The Illinois State's Attorney for Cook County
- Badass Baritone: Jefferies has quite a deep gravely voice.
- Beleaguered Bureaucrat: He sees the world through a political prism in contrast to Stone.
- Da Chief: To the prosecutors and investigators of the State's Attorney's office.
- Expy: Of Battalion Chief Wallace Boden.
- Semper Fi: was a U.S. Marine who served in combat during The Vietnam War
ASA Anna Valdez
Fellow ASA to Peter Stone
Chief Investigator Antonio Dawson
The Chief Investigator for the State's Attorney Office of Cook County. He was previously a detective with the Chicago Police Department, but decided to make a career shift in order to have more time to spend with his children.
- Crossover Ship: With Sylvie Brett.
- Fair Cop: Well, fair investigator now.
- Good Parents: He is a doting, caring father to his son Diego and daughter Eva. One of the reasons he opted for a job change is to have more regular hours with his children for what little time he gets to spend with them.
- Nice Guy: Antonio Dawson, definitely.
- Transplant: He was a cast member of Chicago P.D. prior to the show.
SA Investigator Laura Nagel
Fellow investigator to Dawson at the State's Attorney Office of Cook County.
- Action Mom: She is an investigator for the State's Attorney's office and has a daughter named Jenn.
- Birds of a Feather: With Dawson. Not only are both are determined investigators but also devoted if estranged parents of their kids and divorced from their spouses.
- Deadpan Snarker: Laura Nagel is this, absolutely.
- Fair Cop: Laura is described as a tough-as-nails investigator who sees each case through the eyes of the victim.
- Recovered Addict: She was prescribed painkillers after being shot on the job. She claims to never have had a problem with the medication and simply moved on once her prescription ran out. Her ex-husband, on the other hand, claims that she did have a problem and argued for, and obtained, full custody of their daughter.
- Visit by Divorced Dad: Gender-flipped example. She doesn't have primary custody of her daughter and a judge saw fit to require a court monitor present on all her visits.