Alpha is a blue and ochre Doberman Pinscher owned by Charles Muntz. He is the leader of the dog pack and is usually found with Beta and Gamma, his lieutenants. Like Dug, he has a collar that allows him to talk, but a minor malfunction makes him sound as if he'd been inhaling helium, giving him a squeaky voice. The real voice for Alpha's translator chip (after Muntz fixes his collar) is a deep, intimidating voice. Russell says he likes the high-pitched voice better than the intimidating one.
Alpha has a very condescending and proud disposition, and looks down on all the other dogs in the pack. When Dug fails to bring Kevin (the bird) to Alpha, he puts Dug in the "Cone of Shame". In the climax of the film, Alpha clashes with Dug inside the airship until Dug finally defeats Alpha by trapping him under the helm and sticking a conical airship instrument housing over the Doberman's head as the "Cone of Shame". Alpha breaks his collar, making his voice high-pitched again, which causes the other dogs to ridicule him and (after Dug commands the real Alpha to sit) bestow the "Alpha" title upon Dug. Following his defeat, he is seen at Russell's promotion ceremony in the film's closing scenes, still wearing the "Cone of Shame". The ending credits suggest he becomes a pet of one of the residents at the Shady Oaks Retirement Village.
In the background, he can be seen panting with happiness once Charles says "treat" to Carl and Russell.
Alpha, Beta and Gamma are chasing Kevin when Dug accidentally trips them, causing them to lose the bird. Alpha tells Dug to "watch the bird's favorite rock and tell them if it moves." Dug accidentally knocks the large rock over, almost squashing Alpha and the rest of the pack. Alpha then tells him to sit in the bird's favorite hole and, while giving a speech to his packmates, gets buried by Dug, who sank through the hole. Alpha is shown getting beat up several more times until he calls "master" to tell him that Dug caused them to lose the bird and that he is a bad dog.
- The howling wolf in Day & Night is actually a modified version of Alpha, similar to how background humans in Pixar films are created from a "Universal Man" as a base.
- It should be noted that Alpha is the character's rank in the pack, rather than his name, as Dug became the new Alpha after defeating him.
- Alpha is a Greek letter of the alphabet, along with Beta and Gamma.
- Alpha seems to hate it when others say that his voice sounds funny, due to his broken collar which makes his voice sound high-pitched.