A Daily Mirror newspaper article claiming hypnotist Paul McKenna was a fraud had made him a "laughing stock", the High Court was told.
Paul McKenna denies having a fake PhD qualification
The 42-year-old TV hypnotist disputes an October 2003 article, which mentioned his "bogus degree" from Lasalle University, Louisiana
McKenna's self-help business now has an annual turnover of £2.5 million.
He said he "utterly rejected" any suggestion his was a "bogus PhD" or that he tried to "defraud my public".
In the October 2003 article, journalist Victor Lewis-Smith, said: "I discovered that anyone could be fully doctored by Lasalle within months (no previous qualifications needed), just so long as they could answer the following question correctly: "Do you have 2,615 dollars, sir?".
McKenna was cross-examined on Wednesday by John Kelsey-Fry QC for the newspaper, which denies libel and pleads justification.
McKenna said he was exempted from seven course units for the hypnotherapy doctorate because of his prior learning, supported by additional material.
He also then produced an original thesis which became the Success for Life tapes.
McKenna, of west London, told Mr Justice Eady, who is hearing the action in London without a jury because of the paperwork involved, that his academic achievement rested in his previous 10 years in the field.
"I think they were well spent in the academic study I engaged in, and the evidence of that is the benefit people have received from techniques I have developed, and the way I have communicated those in user-friendly language so that more than half a million people to this day choose to take notice of them," he said.
McKenna's QC, Desmond Browne, has said it emerged that Lasalle was accredited by the council for post secondary Christian education, which turned out to be a fraudulent creation of the university's founder, Thomas Kirk.
McKenna did not know this until after he had submitted his final project.
The hearing continues.