Rick Grimes: Before the zombie apocalypse, Rick was a police officer in the small town of Cynthiana, Kentucky. While in a shootout against an escaped convict with his partner and best friend, Shane Walsh, Rick is wounded and subsequently awakens from a coma some time later. After being mistaken for a zombie and hit over the head with a shovel by Duane Jones, Duane's father Morgan takes Rick in and informs him about what unfolded during his coma. In search of his wife, Lori, and son, Carl, Rick heads to Atlanta, where it is said people were taken for protection. Rick runs out of gas and stops at a farm. Rick finds the owners inside who have committed suicide. Rick throws up outside and searches their barn where he finds a horse. Upon arrival, Rick is saved from a large group of zombies by a fellow survivor named Glenn, who takes him to a camp where Rick is reunited with his wife Lori and son Carl, as well as Shane. Tension between Rick and Shane over leadership of the group and Lori's affections boils over in a confrontation, which ends with Carl shooting Shane to protect his father. Afterwards, Rick leads the group away from Atlanta, trying to find shelter and safe haven from the undead.
Daryl Dixon (Norman Reedus) is Merle's little brother. A Southern redneck with a tough background, Daryl is a survivalist and member of the Atlanta band who quickly becomes one of Rick's closest confidantes and a leader within the group, a role he is not entirely comfortable with. After the fall of the prison, he escapes with Beth who is later kidnapped while he fights off a group of walkers. He joins a nomadic group (the Claimers) before turning on them to save Rick, Carl, and Michonne.
Sgt. Abraham Ford is a survivor and recent member of the military. He is attempting to deliver Eugene to Washington DC, believing he has the answer to the cause of the zombie plague.
Tara Chambler (Alanna Masterson) is Lilly's sister. After welcoming The Governor (under the alias "Brian Heriot") into their apartment, Tara comes to rely on him and follows him as he leads them to join a larger group and lead an attack on the prison, though she refuses to fight when confronted with The Governor's true nature. Glenn discovers Tara in the aftermath of the battle and she agrees to stay with him until he finds Maggie. They later meet Sgt. Abraham Ford, Dr. Eugene Porter, and Rosita Espinosa. She travels with them and they eventually find Maggie, Bob and Sasha before finding Terminus and being captured.
Rosita Espinosa is a survivor of the zombie apocalypse and a member of Sgt. Abraham Ford's survivor group, with whom she is in a relationship.
Beth Greene (Emily Kinney) is Hershel's youngest daughter and Maggie's younger half-sister. She sinks into a deep depression after watching her mother, half-brother and neighbors, who had become walkers and were being housed in her father's barn, get shot by Rick's group and attempts suicide, but changes her mind. She recovers and survives the fall of the farm before travelling with the group to the prison. She is often seen helping to take care of Judith. When the prison becomes infected with the flu, she is put in charge of isolating the group's children to protect them from the deadly virus. She witnesses her father's death at the hands of The Governor and escapes the fall of the prison with Daryl. When they become separated during a walker attack, she is kidnapped. She reappears in season 5 in a hospital where she wakes up after being kidnapped. She then starts to work at the hospital.
Maggie Greene (Lauren Cohan) is Hershel's daughter and Beth's older half-sister. A tomboy at heart, she scavenges supplies from the local town. She develops strong feelings for Glenn, impressed by his bravery and loyalty to the group. After the fall of the farm, she settles at the prison with the rest of the group. Maggie and Glenn are captured by Merle. That’s all that happens. Rick's group rescues them. She helps defend the prison during The Governor's first attack, and kills the sniper stationed in the guard tower. She accepts Glenn's proposal of marriage and participate in Rick's successful ambush on The Governor's second attack on the prison. She guards the prison until Rick's group returns with the Woodbury survivors. When Glenn is infected by deadly influenza virus that spreads to many survivors, Hershel decides to risk exposure by caring for the sick, which fuels Maggie to take out her frustrations by killing walkers near the fences. She manages to rescue her father and fiancee by killing the reanimated infected that overrun the quarantine zone, before Daryl's group returns with medicine. When the Governor arrives at the prison, Maggie witnesses their father's execution, and they participate in the defense against the Governor's militia. Maggie is separated from Glenn and Beth, and flees the compound with Sasha and Bob. The three later discover the prison bus, with all the inhabitants dead and reanimated as walkers, but is relieves to discover that Glenn is not among them. The trio then find a Terminus sign and all go towards it while leaving Glenn messages to follow. The three later find Abraham, Rosita, and Eugene and all of them rescue Glenn and Tara in a walker-filled tunnel. The group then decides to travel to Terminus where they are captured.
Carl Grimes (Chandler Riggs) is Rick and Lori's son, and Judith's older brother. Confronted with the harsh realities of his new world, he quickly learns to defend himself and even rescues Rick from a reanimated Shane. In the prison, when his mother dies during childbirth, he shoots her in the head to prevent her from turning. The ease with which he shoots a member of The Governor's militia troubles Rick, leading him to give up his authority over the group and teaching Carl to farm, renouncing violence. When The Governor attacks for the final time, he and Carl are separated from the rest of the group. With Rick severely injured and unconscious, Carl reveals his anger towards his father for failing to protect the group and his mother. He loots neighboring houses for supplies but is nearly overcome by a walker. He returns to the house and reveals he still depends on his father, and can't bear to bring himself to shoot Rick if he does turn. Rick eventually recovers and they are reunited with Michonne, but are driven from the house by the Claimers. They later meet the Claimers again on the road, where one of the members nearly rapes Carl. After overcoming them with Daryl's help, they travel to Terminus and are captured.
Michonne (Danai Gurira) is a resourceful, self-sufficient, katana-wielding survivor. She first appears as a hooded figure accompanied by two walkers chained to her side-by-side, with their arms and jaws cut off (to prevent them attacking her or anyone else), who saves Andrea from walkers after she is separated from the group when the farm is overrun. When Michonne and Andrea are taken to Woodbury, Michonne immediately becomes suspicious of The Governor. She departs Woodbury, which causes The Governor to send Merle and his men to kill her. She escapes and travels to the prison where she is taken in by Rick and the group. She assists Rick's group in rescuing Glenn and Maggie, but is looked on with suspicion when she abandons the group to attack The Governor directly. When she returns to the prison, she begins to gain the group's trust. The Governor offers Rick peace if he hands over Michonne, and Rick considers it before Merle kidnaps her and decides to hand her over, but changes his plan and lets her go to fight The Governor's army alone, which leads to his death. After the prison group drives away The Governor's army, Michonne and Rick travel to Woodbury, where they discover Andrea dying from being bitten. Michonne is deeply saddened by the situation, and she stays by Andrea's side when she commits suicide. Michonne later returns to the prison with Rick's group and the Woodbury citizens. Months later, she maintains an ongoing search for The Governor. During a supply run to get medicine, she is convinced by Tyreese to stop her search for the Governor. The Governor captures her along with Hershel, but she escapes when the prison group engages The Governor's group in combat, and later saves Rick's life by running The Governor through with her katana. She escapes the prison with another pacified walker acting as her camouflage, but rejects her isolation and tracks down Rick and Carl. She and Carl go on a supply run, where she reveals to him that she had a three-year-old son, Andre Anthony, who died shortly after the apocalypse. Her lover and Andre's father Mike and Mike's friend Terry eventually became her first walker pets. After reuniting with Rick, who escaped their safe house from raiders, the three proceed towards "Terminus", where they are captured.
Carol (Melissa McBride) is Sophia's over-protective mother and Ed's abused wife. She has a kind heart and puts the good of the group ahead of her own needs, but is weak and dependent on the group for survival. When her daughter, Sophia, goes missing she convinces the group to continue searching for her, though they eventually discover her in a barn full of walkers kept by Hershel. Throughout the third season she continues to grow into a dependable fighter and survivor and manages to keep herself alive after being separated from the group, when the prison is overrun with walkers. In the 7 months leading up to Season 4, Carol has started a story time program for the younger kids from Woodbury, which is actually a cover for her self-defense and weapons training course for the children. She keeps the class a secret from Rick and the rest of the survivors. When the father of two children, Lizzie and Mika, dies following a walker attack, she becomes their adoptive mother. Despite Carol's urges, Carl, who has witnessed one of her sessions, tells Rick of her weapons training. Carol kills Karen and David in "Infected, as she believed they were a threat to the group due to their infection with the flu which had not yet spread to others within the prison. Rick banishes Carol from the group, giving her a car and supplies so she can make it on her own. She returns to the prison just after its destruction and later encounters Tyreese, Lizzie, Mika and Rick's baby daughter Judith. She is surprised that Tyreese does not know yet of her involvement in Karen's death, and the group proceeds towards "Terminus", a possible sanctuary. Carol, Tyreese, Lizzie, Mika, and Judith later find a house in good condition and decide to stay there for a while before advancing to Terminus. Carol is disturbed by Mika's refusal to kill dangerous people, but more concerned with Lizzie's refusal to see the walkers as dangerous, though her fears are alleviated when Lizzie helps kill walkers during an attack. When Carol and Tyreese return from gathering food, they discover to their horror that Lizzie has murdered Mika in order to convince them that walkers are just changed humans. Carol realizes that Lizzie is seriously ill and a danger to other people. She concludes that she can neither be left alone nor allowed to be around other people and executes her. She reveals her responsibility for David and Karen's death to Tyreese, who forgives her. Carol, Tyreese, and Judith then set off for Terminus, but their whereabouts are unknown at season's end.
Dr. Eugene Porter is a survivor of the apocalypse and a member of Sgt. Abraham Ford's survivor group. He claims that he knows what caused the outbreak and was headed to Washington to find the "cure".
Glenn Rhee (Steven Yeun) lived in Atlanta, where he delivered pizzas to make a living. He is very much aware of the extreme danger of his missions on behalf of the group, but because of his loyalty to the group he is willing to take the risks. His knowledge of every shortcut in Atlanta proves extremely useful, and he is an excellent scavenger. Glenn thinks well on his feet and shows great compassion and humanity. Despite all the horrors he's seen, he maintains an enthusiasm for life and its unexpected pleasures. He is an integral part of Rick's group, showing surprising depth and emotion when the group experiences devastating tragedy.
Sasha (Sonequa Martin-Green) is Tyreese's younger sister. She travels with her brother's group to the prison and eventually to Woodbury, where she becomes a guard at Woodbury's walls alongside her brother.
Tyreese (Chad Coleman) is the leader of a group that includes his sister Sasha and Allen's family. His group initially seeks refuge at the prison, but Rick drives them out while hallucinating about Lori. They find their way to Woodbury and become guards at Woodbury's walls but later leave.