The sum, which includes legal costs, is a record under the Licensing Act, according to the Trading Standards Institute.
Mohammed Salim, of Costcutter in The Green, has also been stripped of his licence after pleading guilty to 19 charges of breaching conditions of his premises licence.
He had already pleaded guilty to selling to children through his staff back in 2007.
Salim was taken to court after an undercover test purchase operation run by Enfield Council’s trading standards team.
Enfield councillor Terry Neville said: “I would like to thank the council’s legal team and our trading standards officers for this outstanding result. Under-age drinking disturbs the peace of our communities and damages youngsters’ lives. We at Enfield Council are determined to protect the quality of life for our residents and our children’s health.”