Cast
Jason Beghe as Sergeant Henry "Hank" Voight, the enigmatic and often mercurial chief of the Chicago P.D.'s Intelligence Unit. Despite his brutal, tough exterior, he is loyal to the cops and detectives serving under him and highly "dedicated" to the victims of the crimes his unit investigates to the point of committing human rights violations, mainly torture, and not respecting the law. He is first introduced in Chicago Fire as a dirty cop who clashes with CFD Lieutenant Matthew Casey after Voight's son, Justin, causes an accident in which a teenager is paralyzed, and Casey, who was first on scene, had intended to testify that Justin was DUI. He is arrested by Det. Antonio Dawson for trying to have Casey silenced by force but is later released from prison and reinstated to the police force by Internal Affairs. As a result, many of Casey's colleagues dislike him, and Casey's superior Chief Boden has a love-hate working relationship with him. It is eventually revealed in the Chicago Fire episode "Let Her Go" that his dirty cop alter ego was part of an undercover operation to catch criminals and other dirty cops. Prior to taking command of Intelligence, Voight worked in the Gang Unit. His father Richard was a former CPD officer who was killed in the line of duty. Voight is a widower; his wife, Camille, died of cancer some years prior. His son, Justin, served in the Army and was killed in the last episode of season 3 while trying to help a friend. Voight took an interest in Erin Lindsay when she was 14 and raised her as his daughter.
Jon Seda as Senior Detective Antonio Dawson (seasons 1–6), an Intelligence Unit detective who previously arrested Voight for harassment and has since worked alongside him. Unlike Voight, he has limits on how far he will go to get criminals off the streets, as shown by the fact that he asks Halstead to stop Voight from killing anyone while on the hunt for Pulpo because he does not want it on his conscience. He and his former wife Laura have two children: Diego and Eva. He is the older brother of Chicago Fire character Gabriela "Gabby" Dawson. In season 4, he is offered a job at the State's Attorney's Office as Lead Investigator, which he accepts. After becoming disillusioned with the job, he returns to the unit in the first episode of season 5. In season 6, Antonio struggles with recovering from a shoulder injury and dependency on the oxycodone he is taking for the pain. After a dealer he owes kidnaps, beats, and rapes his daughter, Antonio, high on oxy, kills him in revenge. Though Voight and Ruzek manage to cover up the incident as self-defense, and Antonio successfully recovers in rehab, mayor-hopeful Superintendent Brian Kelton later gets the case reopened in order to take down the Intelligence Unit, and in the season finale, Antonio relapses after Ruzek is arrested after taking the blame for everything to protect him. In the season 7 premiere, it is revealed that Voight found Antonio and checked him into an off-the-books rehab clinic to get him clean again while also protecting his career. It was revealed several episodes later that Antonio resigned and moved to Puerto Rico to spend more time with his family. He was replaced by Vanessa Rojas in season seven.
Sophia Bush as Detective Erin Lindsay (seasons 1–4), a tough Intelligence Unit detective and former CI whom Voight took under his wing when she was a juvenile delinquent. Because of this, she is closer to Voight than the other members of the unit. She has a half-brother, Teddy Courtney, who was taken by a pedophile ring at age thirteen and was found turning tricks in New York City 10 years later. She was in a relationship with her partner Jay Halstead from seasons 2 to 4. Near the end of the fourth season, Lindsay is accused of assault after she sticks her gun down a pedophile's throat in the interrogation room; facing possible dismissal from the police force, she accepts a job offer at the FBI in New York and leaves Chicago.
Jesse Lee Soffer as Senior Detective Jay Halstead (seasons 1–10, guest season 13), an Intelligence Unit detective who was Detective Lindsay's partner. A former Army Ranger, he is confident in his abilities and sometimes comes across as cocky. He also has post-traumatic stress disorder, shown progressively during Season 5, later seeking therapy for it. He is the younger brother of Chicago Med character Dr. Will Halstead. He was in a relationship with his partner Erin Lindsay from season 2 until she transferred to the FBI in New York at the end of season 4. He later marries fellow detective Hailey Upton in season 9. Following Olinsky's death and Antonio's resignation, Halstead becomes Voight's right-hand. He later resigns from the force early in season 10 after becoming disillusioned with the gray area the Intelligence Unit has to work in, and returns to the Army in a new job hunting drug cartels in Bolivia.
Patrick John Flueger as Officer Adam Ruzek, a younger police officer recruited straight out of the academy by Olinsky to do undercover work. Early in the series he is often portrayed as an overeager amateur who dives headfirst into a situation without thinking. His parents are separated, and he split time between his father, "Disco Bob" Ruzek (Jack Coleman), a longtime patrol officer with the 26th District who lives in Beverly, and his mother in Canaryville. He was engaged to fellow police officer Kim Burgess before commitment issues end the engagement, but he and Burgess continue to have an on-and-off relationship over the following years, including a pregnancy and its loss (after Burgess is assaulted by a suspect) and adopting a young girl after the girl's immediate family is murdered and other relatives are unable to care for her, before finally getting engaged again in season 11.
Marina Squerciati as Detective Kim Burgess, a former flight attendant turned uniformed patrol officer who was Atwater's partner. She was then partnered with Sean Roman before his departure. Burgess is shot in "Called in Dead" and spends the next episode recovering. She was engaged to Adam Ruzek; the relationship is later broken off because of commitment issues. She later develops feelings for Roman before he moves to San Diego. In season 4, she is offered a job in Intelligence, which she accepts. She and Ruzek continue to have an on-and-off relationship over the following years, including a pregnancy and its loss (after Burgess is assaulted by a suspect) and adopting a young girl after the girl's immediate family is murdered and other relatives are unable to care for her, before finally getting engaged again in season 11. In season 12, she is promoted to detective following the departures of Halstead and Upton and the murder of Emily Martel.
LaRoyce Hawkins as Officer Kevin Atwater (seasons 1–13, guest season 14), a uniformed patrol officer who was Burgess' former partner until he was promoted to the Intelligence Unit. He is responsible for caring for his younger siblings, his brother, Jordan, and sister, Vanessa. After his brother testifies to a grand jury about a crime he witnessed, and Vanessa is threatened with rape for her brother being a snitch, he sends them to live with their aunt in Texas.
Archie Kao as Detective Sheldon Jin (season 1), a tech and surveillance expert. He was discovered to be a reluctant mole working for Internal Affairs sergeant Edwin Stillwell, who had leverage to make him cooperate. He is found murdered in the first-season finale episode, "A Beautiful Friendship".
Elias Koteas as Senior Detective Alvin Olinsky (seasons 1–5; guest season 11), a veteran undercover officer and a friend of Voight who previously worked with him in the Gang Unit. Before joining the force, Olinsky served in the 173rd Airborne Brigade Combat Team stationed in Vicenza, Italy. Olinsky mentions in "Called in Dead" that he has eight confirmed kills in the line of duty. At the end of the fifth season, Olinsky is arrested for the murder of Kevin Bingham, the man who murdered Voight's son, Justin, and is later stabbed to death via a hit in prison while awaiting trial.
Amy Morton as Sergeant Gertrude "Trudy" Platt (season 2 – present; recurring season 1), a sarcastic desk sergeant of District 21, and the immediate superior of the district's patrol officers. Before taking a desk job, she was a uniformed patrol officer, and worked with Dawson. She passed the detective's exam twice. Platt is married to Chicago Fire character Randy "Mouch" McHolland.
Brian Geraghty as Officer Sean Roman (seasons 2–3; guest season 7), a brash patrol officer who partners with Burgess after transferring to the 2-1 from District 31. He transferred out because of his relationship with Jenn Cassidy (Spencer Grammer), who is now a K-9 officer, to avoid breaking fraternization rules. He has his own private security company on the side. After being wounded in the line of duty, and with the department feeling he would be unable to return to patrol, he resigns and decides to join the San Diego Police Department.
Tracy Spiridakos as Detective Hailey Upton (seasons 5–11, guest season 13; recurring season 4), a tough former robbery-homicide detective and Erin Lindsay's replacement following her departure to New York. Upton gets transferred to the FBI field office in New York City in season 7 episode 18, "Lines", to temporarily fill in for an agent undercover. She has great relationships with her CIs and goes to many lengths to protect them. Despite a dark turn in Season 7, she is mostly a "by the book" detective. She was married to former Detective Jay Halstead, however, they have gotten divorced in the beginning of season 11. After going through several traumatic events during seasons 10 and 11, including rescuing Voight from a serial killer at the end of the latter season, she leaves Chicago PD to start fresh.
Lisseth Chavez as Officer Vanessa Rojas (season 7), a rookie and Antonio Dawson's replacement following his resignation. She previously worked in an undercover operations unit. She leaves Intelligence after the seventh season for reasons unknown.
Benjamin Levy Aguilar as Officer Dante Torres (season 10 – present; guest season 9), a recruit who has a complicated past and was recruited under Detective Halstead's wing.
Toya Turner as Officer Kiana Cook (season 12), a former tactical officer demoted to patrol by her supervisor after having noted his tendencies to avoid any real work to preserve his pension. She catches the attention of Intelligence after helping catch the killer of their latest addition Detective Emily Martel, and is later recruited by Voight after helping regarding a case of teenage girls killing their abusers. She later takes a permanent position in the 17th District following the Intelligence Unit's disbandment at the end of the twelfth season.
Arienne Mandi as Officer Eva Imani (season 13), a special agent from the ATF who transfers to Intelligence after helping on the case that brings the unit back from suspension.
