Petraeus gave the keynote address at the University of Southern California's annual dinner for veterans and ROTC students. The retired four-star general tried to clear the air right from the beginning. He offered an apology for the affair that ended his career.
See timeline of the Petraeus-Broadwell affair
"I join you keenly aware that I am regarded in a different light now than I was a year ago," he said. "Please allow me to begin my remarks this evening by reiterating how deeply I regret and apologize for the circumstances that led to my resignation from the CIA and caused such pain for my family, friends and supporters."
Petraeus stepped down as head of the CIA in November after admitting to having an affair with biographer Paula Broadwell. The affair and his close relationship with Florida socialite Jill Kelley shocked Washington and the military and raised serious questions about the women's access to the nation's top spy.
There were concerns that CIA secrets could have been revealed, but Petraeus insisted that was never the case. An independent panel confirmed no secrets were released because of his affair.
Petraeus, who is credited with turning the war around in Iraq, told the crowd more needs to be done to recognize all of our veterans.
In ending his speech, the former general said he knows he cannot take away the pain he caused, but he can learn from his mistakes.
"Perhaps my experience can be instructive to others who stumble or indeed fall as far as I did. One learns after all that life doesn't stop with such a mistake. It can and must go on," said Petraeus.
The crowd of about 600 people gave Petraeus a standing ovation. His wife of 38 years did not attend the event.
On Wednesday, Petraeus wrote an op-ed in the Wall Street Journal that focused on military service members returning to civilian life and getting them back into the workforce.
