Christopher Eddlestone, aged 51, of Neville Street, Longridge, appeared at Preston Magistrates Court yesterday (Wednesday).
He was scheduled to stand trial but decided to plead guilty to the allegations instead.
RSPCA inspector Lisa Lupson said: "Bernard was emaciated and suffering from severe diarrhoea when we found him. He was tethered up outside with a choker chain, had no shelter or bedding and no access to water. He really was in a terrible state."
Mr Eddlestone was banned from keeping any animals for five years; sentenced to a three-month curfew order between 7pm-7am during which time he will be electronically tagged; ordered to pay £3,000 costs and Bernard was confiscated.
In mitigation, the court heard that Mr Eddlestone's mother had been Bernard's main companion until her death 18 months ago. Magistrates were told that Mr Eddlestone had found it difficult to care for the dog since.
Inspector Lupson said: "I'm very pleased with the sentence passed. It shows how seriously magistrates took the case.
"I'm hopeful that banning Mr Eddlestone from keeping animals will prevent any others from suffering, and that is of course, the RSPCA's ultimate intention."
Bernard has been placed with a family who'll now look after him permanently.