Dale is the oldest member of Rick Grimes' group and is respected among the other survivors for his wisdom and his willingness to speak his mind. He acts as the group's "moral compass", trying hard to help the survivors maintain some level of humanity and civility in the post-apocalyptic world.
Over time he, Andrea, and Amy form their own little family unit and he finds spending time with them has helped bring him back to life in a way he never anticipated. Dale is a fairly self-sufficient man, and ever watchful of the changing dynamics among the survivor community. He is known to occasionally deceive and withhold information from the group if he feels it is in the group's best interest.
Dale had been travelling across the United States prior to the zombie outbreak following the death of his wife Irma. He had reached Atlanta by the time the outbreak occurred and he came to the aid of Andrea and Amy, rescuing them and sheltering them in his Winnebago until they eventually found the abandoned quarry where Shane Walsh and several other survivors had established a camp site. While in the camp, Dale served as a lookout and his RV became a "command post" for the camp. As well as looking out for zombies and other threats, he also acted as an unofficial morale officer, helping to keep people's spirits up with stories of his past and sharing his philosophical worldview with the others.
When the camp packs up and leaves the quarry, Dale becomes suspicious of Shane after spotting him scoping out Rick through his rifle's scope. Later, after the survivors are granted shelter in the CDC by Edwin Jenner, he becomes concerned about Andrea, who lost her sister during a zombie attack on the camp. When Jenner informs the group that the CDC building is going to self-destruct, Dale is distraught to hear Andrea say that she wants to stay behind and die when the building explodes. He is baffled by her words and outraged that she came into his life and made him care about her only to give up by trying to commit suicide, and so he decides to stay with her. Andrea cannot accept being responsible for Dale's death and so she and Dale then decide to leave just before the building explodes.
In the second season, when the survivors take refuge at the Greene Farm, Dale and Andrea become somewhat distant as Andrea has lost her trust in Dale after he "forced" her to continue living. While they try to repair their relationship, Dale also becomes increasingly wary of Shane, who is becoming more unstable with each passing day. He believes that Shane fits this new undead world perfectly and is apalled by the idea that he might drag the rest of the group down with him, casting off their humanity and willing to shed the blood of the living just as easily as the dead.
In the episode "Judge, Jury, Executioner", Dale storms off after the rest of the group debate on how to deal with Randall, a survivor from another group that Rick took prisoner. He ventures out into a field where he finds one of Hershel's steers laying disembowelled on the ground. He is suddenly attacked by a zombie and struggles desperately to get it off him, but the creature manages to rip open his abdomen. The others come to his aid but Hershel is unable to help him. Dale is suffering and so Daryl mercifully shoots Dale in the head, putting an end to his pain.