Antonio Jorge Perneta da Silva (46), of Route de la Haule, St Peter, was found asleep in his car in Goose Green car park after a member of the public reported him to the police for driving over the centre white line.
He was breathalysed and found to have 53mg of alcohol in 100 millilitres of breath. The legal limit is 35.
Magistrate Bridget Shaw fined him £2,000 and warned him that if he does not pay, he will face six weeks in prison.
Outlining the case, Centenier John Camara said that the States police received a call from a member of the public at 6pm on 1 June about someone driving a black Mercedes on Victoria Avenue.
They told the police that the driver had clipped the pavement, was swerving along the road and had gone over the centre line.
During a search of local car parks, the Mercedes was found at Goose Green, with the driver, da Silva, sleeping in the vehicle with the keys in the ignition.
He was arrested and taken to police headquarters.
Advocate Estelle Burns, defending, said her client had been drinking in the market and had three or four strong beers.
She said: ‘Mr da Silva admitted it was a silly mistake and he can’t explain why he did it.
‘He wants to apologise to the court and says it will never happen again. He is embarrassed by his actions.’
As well as being fined, da Silva was banned from driving for 16 months.
