Dramatic video recorded back in October showed the puppy's owner, 74-year-old Richard Wilbanks, wrestling with an alligator that had snatched Gunner the Cavalier King Charles Spaniel from the edge of his backyard pond.
TOP TRENDING: Florida man wrestles his puppy from jaws of alligator
The video, with its miraculously happy ending, quickly went viral.
At a special ceremony for Gunner, the county sheriff said the puppy's survival instinct makes him a perfect candidate for the county's "Pets on Patrol" program.
"Do you swear to uphold the Constitutional law for the Lee County Sheriff's Office, Gunner?" said Sheriff Carmine Marceno. "Ok. This is a big day, okay? You are going to be a detective now. Here we go."
The Deputy Dogs program encourages pet owners to be on the lookout for suspicious activity.