(ABC NEWS) -- David Petraeus apologized in front of an audience of about 600, who welcomed him with a standing ovation, for an extramarital affair with his biographer in his first public speech since resigning as the head of the CIA.
"Needless to say, I join you, keenly aware that I am regarded in a different light now than I was a year ago," Petraeus said Tuesday night to an audience of mostly veterans at the University of Southern California's annual ROTC dinner at a hotel in Los Angeles.
"I am also keenly aware that the reason for my recent journey was my own doing. So 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 said.
The decorated war hero and former four-star general has remained out of the public eye since his affair with writer Paula Broadwell was revealed in November.
The former commander of U.S. and ISAF forces in Afghanistan addressed the affair only one other time in a statement the day he resigned as CIA director.
"After being married for over 37 years, I showed extremely poor judgment by engaging in an extramarital affair," Petraeus confessed in a letter to CIA staff.
Since announcing his resignation, Petraeus has only appearing in closed-door hearings before the House and Senate intelligence committees to testify about what he learned first-hand about the Sept. 11 attack in the U.S. Consulate in Benghazi.
"I know I can never fully assuage the pain that I inflicted on those closest to me and a number of others," Petraeus said Tuesday.
Petraeus' wife, Holly, was not in attendance at the dinner.
"As I close, I want to say thank you for words of encouragement to family. ... This has been difficult episode for us ... to fall as far as I did," Petraeus said in his closing remarks before he received another standing ovation.
Petraeus, 60, spent much of his time at the ROTC dinner speaking about what can be done for veterans and the families facing transition challenges from military life to civilian life.
"In reality, the transition often is quite challenging. Hanging up the uniform is quite difficult," he said.
Petraeus also penned an op-ed in the Wall Street Journal about helping veterans find employment, assimilate into the workforce and set them on a definitive career path.
The speech and op-ed are Petraeus' first steps in what appears to be a carefully choreographed comeback bid as he tries to rehab his once-pristine image.
Petraeus' affair with Broadwell was discovered during an FBI investigation into emails she sent to Florida socialite Jill Kelley.
Broadwell, 40, who is also married, wrote the biography on Petraeus, "All In."
ABC News' Maria Nikias contributed to this report. Click here for more from ABC News.