Brian Whitlock, 26, entered his guilty plea on Tuesday and is expected to be sentenced in June.
Last July, a two-year-old German Shepherd named Captain was found in a dumpster in the Vancouver neighbourhood of Kitsilano. The dog was wrapped in a bloody blanket, emaciated, stabbed, cut and brutally beaten.
Captain died of his injuries soon after he was found.
Dog owners and animal rights groups held vigils and organized protests calling for an end to animal cruelty.
The groups, Justice for Captain and For the Love of Captain, have been following the case through the courts. On Tuesday, supporters gathered once again outside the Vancouver courthouse where Whitlock appeared.
"We're definitely pleased that he pleaded guilty, this was case that touched so many people's hearts," said Marcie Moriarty of the SPCA.
"A guilty plea shows that we put together a strong case for Crown. It also shows that [Whitlock] is taking responsibility and it avoids the emotional turmoil that can happen with a trial."
Whitlock now faces a possible sentence of up to five years in jail, a $10,000 fine, and a lifetime ban on owning or having custody of animals.
Moriarty said the SPCA is hoping for a life-time ban and jail time.
"He's demonstrated clearly that he has no business of having the pleasure of animals around," she said.