Nothing is known about Dog's life prior to or as the outbreak began. It's possible he was born after the outbreak.
At night, as Carol gives Daryl a haircut, Dog leaves to walk around. Later, as they have dinner, Henry asks Daryl how he got his scar on the eye but he ignores him and leaves to find Dog.
Henry tails Daryl and finds a walker instead. Daryl shows up and asks if he was following him. Suddenly, Daryl hears Dog barking wildly nearby and rushes over to find it stuck in a trap and surrounded by walkers. Daryl picks off the walkers to save Dog and before a walker can bite him, Henry jumps in and saves him. "I told you to stay back", Daryl scolds. Back at the camp, Daryl pets Dog as he talks with Henry about moving to Hilltop.
In the morning, Daryl loads up his bike for Hilltop and Carol seems overjoyed she convinced him to come. They drive to Hilltop with Dog riding with Carol and Henry on their cart. Later, they arrive at Hilltop and hug Tara. Aaron greets Daryl and tells him they could use his help locating Eugene, to which he agrees.
With Dog leading the way, Daryl, Aaron, and Jesus head out to find Eugene.
Dog accompanies the search party and eventually finds Eugene hiding beneath a trapdoor in a barn.
As a herd of walkers close in on them, Daryl takes Dog to draw them away from the rest of the group. Using firecrackers and Dog's barking, they manage to get the attention of the herd but Daryl is shocked to see the herd turn away and continue on their original path.
Dog was with Daryl, Michonne, Aaron, Magna, Yumiko, and Eugene as they escaped from the cemetery that was filled with both Walkers and Whisperers. Sensing the Walkers and Whisperers at the bridge, Dog barked to get Daryl and friends' attention. After Daryl and Michonne nabbed Lydia, Dog safely escorted them back to Hilltop with Jesus' body. According to Daryl, Dog picked the barn for him and Daryl to sleep over night at Hilltop.
After Henry disappears with Lydia, Daryl calls upon Dog to track them down. Dog is able to lead Daryl to the two's escape route and Daryl sends him off again. Dog is then seen with Daryl and Connie as they exit the Hilltop to go after Henry.
Dog accompanies Daryl and Connie on their search for Henry and Lydia. Dog leads the two to Henry's dropped fighting stick and shows them the way the Whisperers went. After Daryl kills a walker, Dog retrieves his arrow but breaks it in the process, leading Daryl to comment "bad Dog."
Dog runs from the Whisperers' camp with Daryl, Henry, Connie, and Lydia. To Daryl's annoyance, Dog follows Connie when she leads the group in a different direction than where he wants to go in.
At an abandoned building, Daryl locks Dog in a closet with Lydia to protect her in case the Whisperers get past them. As Henry is almost killed by a Whisperer, Dog begins growling so a desperate Lydia breaks down the door for him to save Henry. Dog tackles the Whisperer off of Henry and begins savaging him, allowing Henry to finish the job by bashing the Whisperer's head in as Dog attacks. After the Whisperers are defeated, Daryl and his group leave for Alexandria to get Henry medical attention before they move on again.
When Daryl's group arrives at Alexandria for medical help for Henry, Dog is with them. As the group leaves, Daryl calls Dog who runs on ahead. They are later picked up by Michonne and Judith on their way to the Kingdom.
When Daryl arrives at the Kingdom, Dog is with him. Later, when he departs for the Hilltop, Daryl leaves Dog behind at the Kingdom and asks Connie to feed Dog for him. Connie leaves with Dog to feed him.
Negan notices that Judith is upset and she explains that Daryl asked her to watch Dog for him while he moved the Kingdom to the Hilltop. However, Dog has disappeared.
As a group moves to Aaron's house for shelter from a blinding blizzard, Judith hears Dog barking and rushes off after him. Negan immediately follows after Judith, finally finding her by following Dog's barking to where he has gotten tangled up. Negan takes Dog's leash and carrying Judith, leads them to an overhang for brief shelter from the storm. When Negan begins to carry Judith to better shelter, she orders him to bring Dog too. Negan takes Dog's leash and takes them to safety from the storm until it ends.
Dog appears on the beach playing with Jerry, his kids, Judith, and R.J. When he sees Connie, he gets excited and plays with her and Kelly. When Connie returns him to his owner, Daryl claims that Dog likes Connie more than he does his own owner.
This list shows the victims Dog has killed:
Dog and Daryl have a good relationship. Daryl is Dog's owner and cares for him greatly, as seen that Daryl goes out of his way to feed Dog, at his own expense. Dog also is seen to listen to Daryl. In "Evolution", Dog starts barking at the herd when the firecrackers go off, to re-route them, but when the plan fails, Daryl commands Dog to stop, which he does without hesitation.
Dog assisted Daryl, Jesus, and Aaron's mission to find and recover an injured Eugene. Using his senses, Dog found Eugene hidden under a barn. He appears to be protective of the injured new friend as he safely escorts him back to Hilltop along with his new friends and his owner.
Dog assisted Jesus with Daryl and Aaron to find Eugene. After Jesus is murdered by the Whisperers, Dog is shown to be protective of the late Jesus as he safely escorts his owner, new friends, and Jesus' body back to Hilltop to bury him.
Dog has a good relationship with Henry from the moment they meet. When Dog gets trapped by a small herd of walkers shortly after they meet, Henry helps Daryl to rescue him. During the fight with the Whisperers, Dog races to Henry's rescue and saves his life from an attacking Whisperer. Thanks to Dog, Henry survives and kills the Whisperer as Dog savages him.
Dog has a good relationship with Connie and trusts her. When Daryl leaves the Kingdom to go on a mission with Michonne, Carol, Magna, and Yumiko, he is left with Connie to feed him, which he accepts by following her to be fed. After Connie brings Dog back to Darryl, Darryl comments that Dog likes her better than him.
It's not sure how Dog feels about Lydia. When they're locked in a closet together, Dog appears to growl at her. However, this could be just to scare her into letting him out to save Henry and Daryl or in response to his friends being in danger outside. As Lydia will be spending a lot more time with Daryl, Dog will most likely bond with her and warm up to her.
Dog appears to trust Judith as Daryl left him with her while he was helping the residents of the Kingdom move to the Hilltop. Judith is very concerned about him when he disappears. As the Alexandrians move from one house to another during the storm, Dog barks, getting Judith's attention, who runs off from the group to save Dog. Judith risks her own life in saving Dog. After a training session on the beach, Dog is seen playing with Judith, R.J., Jerry, and his kids on the beach.
- "The Calm Before"
- "The Storm"
- During the "In Memoriam" on Talking Dead for "Stradivarius", the walkers that ambushed Dog are billed as Dog Walkers.
- Norman Reedus once asked the writers and crew if Daryl could get a dog, but that request was initially denied until Season 9.
- Dog not letting go of Daryl's arrow in "Guardians" and breaking it was originally not meant to happen, but Norman Reedus improvised and kept that scene going by adding his line "bad dog".
- As of his first appearance in Season 10, Dog will have surpassed Shiva as the animal with the most appearances in the TV Series.