John Nolan is a older rookie who is trying to start a fresh new life in LA after facing a divorce and being caught in the middle of a bank robbery. He is the oldest rookie of the Mid-Wilshire division. Despite this he is a very comited and dedicated person to his job.
Lucy Chen is young women looking to become a police officer. Her training officer is Tim Bradford who trains her well. In one of the earlier seasons she gets abudcted by A man and then locked in a barrel which makes her life on the job worse.
Jackson West is a youn man who has always wanted to be a cop. His dad was a cop and this made him determined to be the best and try his hardest to make his father proud. His training officer is Angela Lopez. He started off as not right for the job but got better and improved a lot.
Nyla Harper is a former detective who got divorced from her husband and was losing the custody battle. Therefore she switched to patrol where she had more regular hours and could have her kid visit her again. She is John Nolan's training officer. She also has a golden ticket from her detective work which means she can't get fired for doing anything unless it is completely unlawful
Tim Bradford also known as "Super Cop" because everyone thinks he does not make mistakes. Has been working for the job for a while and after his wife left him and started using drugs he couldn't focus on the job but after a while he regains his work and is the hardest training officer on his rookies. His rookie is Lucy Chen and he trains her very harshly but also forgiving.
Angela Lopez is good training officer. However on the first day of her job she gets into a shootout and one of her fellow officers dies in her arms. After that moment she had changed a lot and took everything much more seriously and with a lot more caution. Her rookie is officer Jackson West and she trains him harsh and tries to fix every mistake he makes.
Bailey is portrayed as strong independet women. She is shown more in later seasons but is ocasionally shown in earlier seasons
Wade Grey is the watch commander for the Mid Wilshire division. He serves as a veteran cop and a mentor for many. He helps Nolan and the other rookies in times of struggle and is always there for people.
Wesley is Angela Lopez's husband. He is a lawyer and is a very sharp man who gets his point across. During one of the seasons he ends up getting stabbed which sets him back in his work.