Wilson was a stray dog from an alternate universe who apparently liked to bark all night and chew on shoes. He was taken by Dr. Braun and his assistants to be a test-subject for the mascara-x project. The mascara-x project was supposed to be a one-time mascara treatment that would regenerate forever. This experiment was supposed to put 'Babeline' cosmetics back into the number-one slot in the cosmetics industry. Wilson's test was deemed a failure and he was tossed into a dumpster behind the lab. Shortly thereafter he arose as Deadpool: Merc with a Bark.
With no where to go, Wilson wandered. Eventually, he arrived at a circus and became the big act - the invincible, unkillable Dogpool. As his act grew, Dr. Braun caught wind of it. After attempting to take Wilson back for testing, Wilson attacked Dr. Braun and his assistants. Braun, in a fit of spurned rage, re-created the accident with a dog he names "Wolverine." Wolverine is unleashed at the circus and fights Wilson. Eventually, Wilson beats Wolverine and is claimed by Deadpool for his ever-growing corps.
Due to the Mascara-X project, Wilson has been granted a healing factor much like his other-dimensional-brethren. He also seems to be quite adept mentally, beating Braun and outsmarting the 'Wolverine' dog early on in his life as a Deadpool. For a dog, he is an impressive hand-to-hand combatant to an extent, but is most notable for deceiving and tricking others to achieve his goals.