The Apprentice boss is arguably Dublin's best example of a self-made millionaire, however he could soon be back to his Penny Apple days.
Cullen (70) has consented to a €8.2m judgment being entered against him at the Commercial Court over unpaid loans to Danske Bank.
But he didn't make it easy for the financial institution.
The court heard three unsuccessful attempts had been made to serve legal proceedings on Mr Cullen at his Sallins home last month before the bank got leave to serve the legal documents by post.
It was revealed how officials visited Cullen's luxurious Osberstown House in Sallins, Co Kildare, on three occasions in an effort to alert him to the bank's cash issues.
Ms Justice Mary Finlay Geoghegan entered summary judgment of €8.2m against the car dealer yesterday.
Counsel for Mr Cullen said he was consenting to judgment and it was anticipated a planned sale of property would reduce the judgment sum.
The ruling is a major blow to Cullen, who was a poster boy for 'ordinary people hoping to make the big time'. He led a rags-to-riches lifestyle, moving from a situation where he was the eldest of an inner-city family of 14 in a one-room tenement to millionaire.
Cullen left school at 13 and worked as a messenger boy and on Moore Street before buying the franchise Renault car distribution for £1 when he was 22.
In the intervening decades he became a household name along with his glamorous partner Jackie Lavin, who helped him front TV3's The Apprentice.
Counsel for the bank told the court that a receiver had been appointed over secured properties and Mr Cullen would be entitled to proceeds from them.
The case arose from a €8.1m loan advanced to Mr Cullen in April 2011 to restructure an existing loan.
The April 2011 facility was to be repaid in full by April 2012 via quarterly instalments, but the bank claimed no repayments were made since November 2011.