Keith Morgan, 56, was touted as a hero after claiming he found 15-year old 'Sammy' in a bag on the side of a road before bringing it to a shelter in March.
But investigators soon learned the dog was his, and he and his wife Ewing, 43, were charged with animal cruelty and filing a false police report.
The pooch was covered in urine, and his fur was so matted together that he couldn't stand.
Sammy the Cocker Spaniel has since recovered.
In addition to the six months in jail, the couple must also pay a $1,000 fine and $13,000 in restitution to the Red Bank Veterinary Hospital. They are also both barred from ever owning a dog again.
At the time they pleaded guilty, about 70 people showed up in court in support of Sammy, wearing T-shirts with his picture on the front.