In a French interview with Radio Ville-Marie, Tremblay said he decided to step down because he felt he could no longer be useful to the people of Montreal.
"My whole political career was to help people," he said.
"I was a lawyer, I got my MBA from Harvard, I could have gone into a big company and made others and myself rich, but I hope I'm not on earth for that. I'm on this earth to make people happy," he said.
Tremblay served as mayor from 2001 to 2012. Though he was never accused of corruption himself, he resigned amid allegations that he turned a blind eye to corruption and electoral misspending by members of his Union Montréal party.
Tremblay said he feels betrayed, but denies that he was naive to trust those around him.
"I put my confidence in certain people, and that confidence was betrayed," he said.
"When we're abandoned by people with whom we worked, with whom we rubbed shoulders for 25 years, when there's no compassion, when there's no recognition, that I found hard. But I've turned the page. It serves no purpose to let it hurt me," he said.
He said he expects the Charbonneau Commission's inquiry into corruption in the construction industry to clear his name and reveal what really happened in his administration.
"It's a puzzle, and the Charbonneau Commission is working to solve that puzzle — and one day they will reveal the reasons why I had to quit," he said.
A philosophical Tremblay spoke of just returning from the Way of St. James pilgrimage to the Cathedral of Santiago de Compostela in Spain.
Asked if the pilgrimage was a way of seeking pardon, Tremblay said his conscience is clean.
"I don't have anything that needs pardoning per se. On the contrary, I just wanted to thank God," he said.
The Way of St. James was his way of turning the page on the past two years, Tremblay said.
"That was to reflect on the future, to thank God for the opportunities I've been given," he said of the 30-day walking trek.
As to the future, Tremblay said it will definitely not involve politics.
"My father said don't go into politics, Gérald. Politics are dirty and they will destroy you," he said.
FOR THOSE WHO DO NOT KNOW THE RECENT HISTORY OF CORRUPTION IN THE CITY HALL OF MONTREAL -
MONTREAL MAYOR MICHAEL APPLEBAUM - PROTESTS LEGITIMATE PROTESTS
MONTREAL MAYOR MICHAEL APPLELBAUM REJECTS A BILINGUAL MONTREAL
MONTREAL MAYOR MICHAEL APPLEBAUM - THE PEOPLE ARE IN THE WAY
MICHAEL APPLEBAUM REPRESENTS MICHAEL APPLEBAUM
MICHAEL APPLEBAUM IS SITTING PRETTY - FOR NOW
HISTORY OF MICHAEL APPLE-BOMB