In a letter to the provincial government, Louis LaPierre said he is sorry for the embarrassment he has caused to his colleagues and others who trusted him.
"During the years, in documents and among various bios, I have misrepresented my academic credentials and have admitted the same to the Universite de Moncton," LaPierre said in the letter, which the government made public Thursday.
"I take full responsibility for my actions and offer a full apology for the embarrassment this situation has caused to so many that placed their trust in me."
In various biographies, LaPierre, 73, said he had a PhD in ecology from the University of Maine. A spokeswoman with that university said it has no record of him earning that degree.
LaPierre was hired as chairman of the New Brunswick Energy Institute, a research body he called on the government to create when he delivered his report on shale gas regulations last year.
In addition to his resignation from the institute, LaPierre said he was stepping down from a variety of academic positions he held at the Universite de Moncton.
Energy Minister Craig Leonard said he was taken aback after hearing LaPierre had misrepresented himself.
"I was obviously shocked," Leonard said.
But Leonard added that he doesn't believe it undermines LaPierre's work on shale gas and the concerns people expressed during public consultations on the development of the industry.
"He provided a report to us indicating what those concerns were, he provided a model of how we could move forward to help address those, obviously focused on more research, more New Brunswick-based knowledge," Leonard said.