Cast and characters
Shemar Moore as Sergeant II Daniel "Hondo" Harrelson Jr., a Los Angeles native who was promoted to team leader in a blatant attempt to ease the tensions between the community and the LAPD after his former team leader shot an unarmed black teenager. He was demoted at the end of season 4 after leaking information of racism in the LAPD to the press before later regaining command early in season 5. As team leader, his callsign was 20-David but it changed to 27-David during his demotion. He knows everyone in the neighborhood and treats them with respect and they usually give him information pertinent to his cases. He once dated Elle Trask, an FBI Agent. He was then in a clandestine relationship with Jessica Cortez, but they were ultimately forced to break it off to protect their careers despite both expressing their love for each other. He later dated Nia Wells, an Assistant District Attorney, but later broke up when he had threatened to go after a man, he accused of drugging his younger half-sister, Briana, at a nightclub to possibly take advantage of her. He then went onto dating Nichelle when they first cross paths helping an injured man following a pursuit of armed robbery suspects that Hondo was in. At the end of the fifth season, Hondo learns that Nichelle is pregnant with their first child. She gives birth to their daughter Vivienne in the sixth season and the two marry in-between seasons six and seven.
Stephanie Sigman as Captain Jessica Cortez (seasons 1–2), Commanding Officer of the LAPD Metropolitan Division and Hondo's lover, and then former lover. She is a respected officer who has plans to improve the relationship between the LAPD and the citizens of Los Angeles, despite some resistance from the rank and file. In the second-season finale, she accepts an offer for an FBI assignment and leaves the LAPD to go undercover. By the start of the third season, she has seemingly taken the assignment permanently, with the actress being confirmed as having exited the show.
Jay Harrington as Sergeant II David "Deacon" Kay, a ten-year veteran of the S.W.A.T. team who was passed over for promotion in favor of Hondo in the aftermath of the Raymont Harris shooting. Although he takes the decision in stride, he later admits to Hondo he was resentful about being passed over, but made peace with it once he saw what an effective leader Hondo was. His callsign is 30-David. He acts as second in command of the team and serves as a mentor to his teammates, also serving as an instructor at the LAPD SWAT academy. He is fiercely dedicated to his job with SWAT and serving the city of Los Angeles, and was even awarded the LAPD Police Star at the end of Season 2. He is also fiercely loyal to his team, particularly Hondo, all of whom he considers family. In the event Hondo is unavailable, Deacon will become 20-Squad's temporary leader, giving orders at SWAT HQ and even in the field. His dedication to the team is only matched to that he has to his wife Annie (Bre Blair) and their three children: Matthew, Lila and Samuel. In "School," it is revealed that his daughter, Lila, is named after a school shooting victim. Midway into Season 2, Annie gives birth to another daughter, Victoria. In Season 3, he takes on a second job working for a private security firm. In Season 7, Deacon starts to see his work life conflict with his family life, leading him and Annie to have disagreements over when he is needed most. After some soul-searching and advice from Hondo and Hicks, Deacon makes the tough decision to retire in order to spend more time with his family and allow Annie to pursue her dreams of becoming an attorney. However, he soon re-evaluates his decision following Luca's shooting and subsequent retirement and 20-Squad's staffing crisis, and eventually reverses his choice after Annie's sister moves in following her divorce to help with the children.
Alex Russell as Officer III James "Jim" Street (seasons 1–6; recurring season 7), a new transfer from the Long Beach Police Department. His call sign is 26-David. His mother Karen (Sherilyn Fenn) was in prison for murdering her abusive husband/Street's father; she was arrested by former S.W.A.T Team Leader Buck Spivey. He initially has trouble adjusting to being part of the team due to his impulsiveness and for abandoning his duties to take care of his mother, which eventually got him removed from SWAT. He has since earned his way back on the team. He continues to have an up-and-down relationship with his mother until her death in the fifth season, as well as romantic tension throughout the series with teammate Chris Alonso, which finally blossoms into a relationship just before Chris leaves the team and the LAPD at the end of the season. In the Season 7 episode, "End of the Road", after helping the team stop a group of criminals, Street transferred back to LBPD to join Long Beach's SWAT team, becoming its new commanding officer after its previous leader died from injuries sustained in a gunfight. It is also revealed Street is engaged to Chris.
Lina Esco as Officer III Christina "Chris" Alonso (seasons 1–5), a former canine officer and (originally) one of the two female cops assigned to S.W.A.T. Her callsign is 24-David. She serves as the Squad's sniper and becomes close friends with Street. Openly bisexual, she enters a polyamorous relationship in the second season, but breaks it off later. Chris is the godmother to Deacon's fourth daughter, Victoria. At the end of the fifth season, after finally starting a relationship with Street, she leaves SWAT and the LAPD altogether to take over the duty of helping and housing illegal immigrant girls seeking asylum in the United States. Esco confirmed her departure from the series in order to pursue other job opportunities. But even after, Chris is still mentioned multiple times in season six, including being engaged to Street, so her character is currently alive.
Kenny Johnson as Officer III+1 Dominique Luca (seasons 1–6; recurring season 7), a third-generation S.W.A.T officer. His callsign is 22-David. He was originally the driver and mechanic of the team's vehicle "Black Betty" until an injury placed him temporarily in a tactical support role until he was allowed to be in the field again. Johnson previously appeared on The Shield, also created by Shawn Ryan. He discovers in the sixth season that officer Eva Durrant is his half-sister. In the last few minutes of the Season 7 episode, "Escape", while responding to a call concerning a robbery, Luca is shot, his fate unknown. In "Last Call", Luca is revealed to have survived the shooting; however, he has suffered permanent damage to his hand and arm. Not wanting to be confined to a desk, Luca decides to retire for good from all policing duties: active duty policing, S.W.A.T., and the LAPD.
Peter Onorati as Sergeant II Jack Mumford (season 1; recurring season 2; guest seasons 4 and 7), the team leader of another S.W.A.T. team alongside Hondo's. His callsign was 50-David. He has been divorced three times; in "Payback," he gets engaged again after only a month-long courtship. In the conclusion of the second season episode "Jack," he announces his retirement from SWAT and the LAPD after being shot earlier in the episode, and makes his retirement official two episodes later. In the fourth season episode "Positive Thinking," Mumford returns to work a 15-year-old cold case.
David Lim as Officer III Victor Tan, a former officer with the LAPD Vice Squad. His callsign is 25-David. He joined S.W.A.T. three years prior to the series. Once on track for a prestigious career at the insistence of his parents, Tan instead decided to pursue his own path in life and chose to become a police officer instead. He is very knowledgeable of the drug trade in Los Angeles from his time on Vice and maintains several connections that he will use during cases. In the season four finale, he marries his longtime girlfriend Bonnie. They later split up halfway through the sixth season after Tan learns she had been cheating on him for months with a client.
Patrick St. Esprit as Commander Robert Hicks (seasons 2–8; recurring season 1), a senior officer with the LAPD Special Operations Bureau. He is a widower and a longtime friend of the Kay family. He has two grown children; a daughter named Molly and a son named J.P. St. Esprit was promoted to a series regular for season 2.
Amy Farrington as Lieutenant Detective Piper Lynch (season 3; recurring season 4), an experienced detective from LAPD Hollywood Division appointed by the mayor as a tactical consultant to Hondo's team.
Rochelle Aytes as Nichelle Carmichael (seasons 6–7; recurring seasons 3–5 and 8), a social worker at the local community center and Hondo's on-and-off love interest since the third season. As of the end of the fifth season, she is pregnant with her and Hondo's first child. In the sixth season episode "Stockholm," she gives birth to their daughter Vivienne. In the sixth season finale, she married Hondo.
Anna Enger Ritch as Officer III Zoe Powell (seasons 7–8; recurring seasons 5–6), a new SWAT recruit who debuts during the fifth season and who takes Chris's place on 20-Squad on-and-off following her departure, before eventually joining the team permanently during the seventh season. She initially reminds Street of himself in the beginning due to her lone wolf attitude, recklessness, and disregard for protocol, but eventually opens up and becomes part of the team.
Niko Pepaj as Officer III Miguel "Miko" Alfaro (season 8; recurring seasons 6–7), a new SWAT recruit who debuts during the sixth season and works with 20-Squad on-and-off until joining them for good at the end of the seventh season. He was formerly from Long Beach and worked with Street on the SWAT team there; the two had a heated rivalry, which came to a head after Alfaro filed an anonymous complaint against Street for allegedly stealing money (which Street was ultimately cleared of). The two ultimately settle their feud after Alfaro transfers to LAPD. Late in the seventh season, Alfaro falls out with Tan, who feels the former is using 20-Squad as a stepping stone to further his own career, though the two settle their difference in the finale.
Annie Ilonzeh as Officer III Devin Gamble (season 8), a new SWAT recruit who debuts during the eighth season. Once a promising rookie LAPD officer from a family of mostly criminals, Gamble's reputation and prospects were ruined after her father murdered a Sheriff's Deputy, forcing her to transfer to the Oakland Police Department and start over there. She eventually returns to the LAPD after Hondo personally recruits her to fill the last available slot on his team, but still faces scrutiny from other officers and personnel who hold her responsible for her father's actions and don't believe she belongs on the job.
