List of 9-1-1 characters

• Angela Bassett as Athena Grant-Nash (née Carter), LAPD patrol sergeant, mother of May and Harry from her first marriage to Michael Grant. Athena left her home in Florida for Los Angeles to become a police officer as a result of the failed investigation into the murder of her friend Tanya Kingston (a murder she helps to solve 45 years later). Athena and Michael divorce in the first season. At the end of season one, she begins dating Bobby Nash and marries Bobby at the end of the second season. Pepi Sonuga portrays a younger Athena during an episode of season 3, in which she discovers that the weapon used to murder her fiancé has been found.
• Peter Krause as Robert "Bobby" Nash, LAFD Station 118 captain and later Athena's husband. A recovering alcoholic, before arriving in Los Angeles Bobby lived in Minnesota where his wife and two children died in a fire in a building that was not up to code, and blamed himself for their deaths and those of 145 other people in the building (the fire was caused by a faulty propane heater he had been using in an empty apartment while he was drunk). Originally planning to commit suicide after saving 145 lives as atonement, his friendship/camaraderie with the members of the 118 and his blossoming relationship with Athena helps him put his demons to rest, and he becomes a beloved step-father to May and Harry.
• Oliver Stark as Evan "Buck" Buckley, firefighter and Maddie's younger brother. Buck was a womanizer at first, but after meeting Abby he started looking for serious relationships.
• Aisha Hinds as Henrietta "Hen" Wilson, firefighter/paramedic. She is married to Karen and together they have a son named Denny.
• Kenneth Choi as Howard "Howie"/"Chimney" Han, firefighter/paramedic and Maddie's partner. At the end of season three they find out Maddie is pregnant and they now have a daughter. He grew up in the Los Angeles area with his mother while his father returned to South Korea. As a result, he has a very testy relationship with his father, especially after the elder Mr. Han openly expressed his disappointment in his chosen profession. He has a younger half-brother named Albert, who secretly left South Korea to escape their father's control and lived with him for a while.
• Rockmond Dunbar as Michael Grant, Athena's ex-husband. The two amicably divorce after he comes out as gay. He and Athena remain close friends and confidants, and the friendship extends to her new husband Bobby. He leaves Los Angeles with his boyfriend David to work in Haiti after David decides to go see how a storm destroyed that country. (season 1–5)
• Connie Britton as Abigail "Abby" Clark, 911 operator.[1] Abby leaves at the end of season one to travel the world following her mother's passing. She never came back to Los Angeles until the season 3 finale to give Buck closure. She ended up engaged and living in Arizona. (season 1; special guest season 3)
• Jennifer Love Hewitt as Maddie Buckley Kendall,[2] 911 operator, Buck's sister, and Chimney's partner. Maddie was in an abusive marriage and ended up killing her husband Doug Kendall in self defence after he stabbed Chimney and kidnapped her. At the end of season three, she finds out she is pregnant with her and Chimney's first child. In season 5, Maddie leaves Chimney and their baby because she doesn't think she would be a good mother for the baby. (season 2 – present)[3]
• Ryan Guzman as Edmundo "Eddie" Diaz, firefighter.[4][5] He joined the 118 fresh out of the academy. A Texas native, he served in the United States Army as a combat medic and moved to Los Angeles after being discharged. He served in Afghanistan and his combat experience is shown through his ability to think quickly on his feet even under duress with minimal back-up. He is a single father and has a disabled son named Christopher. (season 2 – present)
• Corinne Massiah as Margaret "May" Grant, Athena and Michael's daughter. Graduates high school at the end of season three. Begins training as a 911 operator in season 4. (Season 2 – present; recurring season 1)[6]
• Marcanthonee Jon Reis as Harold "Harry" Grant, Athena and Michael's son (season 2 – 6; recurring season 1)[6]
• Gavin McHugh as Christopher Diaz, Eddie's son. (season 3 – present; recurring season 2)[7]
• John Harlan Kim as Albert Han, Chimney's half-brother. (season 4; guest seasons 3, 5)

This is a list of recurring actors and the characters they portrayed in multiple episodes, which were significant roles, sometimes across multiple seasons.

The following is a supplementary list of guest stars, some recurring, who appear in lesser roles.