His remarks came in the wake of a Washington Post story that quotes several former Romney schoolmates by name as they recall the presidential wannabe holding down a classmate and forcibly cutting his long, bleached-blond bangs after disparaging the boy's appearance.
"Back in high school, I did some dumb things," Romney said during a Fox News Radio interview, although he added he doesn't remember the incident.
"And if anyone was hurt by that or offended, obviously I apologize for that."
In 1965, at least five students at Cranbrook all-boys high school in Michigan witnessed the attack, according to the Post report.
Romney, then the teenaged son of the Michigan governor in his final year of high school, was outraged by his classmate's appearance, led a cheering gang of students in an attack against the boy, pinned him to the ground and hacked off locks of his hair.
"He can't look like that," Romney told a close friend at the time. "That's wrong. Just look at him!"
The timing of the story couldn't be worse for the Romney campaign, appearing a day after President Barack Obama became the first president in U.S. history to throw his support behind same-sex marriage. His administration is being celebrated by civil libertarians and the country's gay community for taking a bold stance on what's considered a modern-day civil rights battle.
Romney, long opposed to same-sex marriage, tried to do some damage control about his attack on the late John Lauber during his radio interview.
"I'm a very different person than I was in high school, of course, but I'm glad I learned as much as I did during those high school years," he said.
"I'm quite a different guy now. I'm married, have five sons, five daughters-in-law and now 18 grandchildren. There's going to be some that want to talk about high school. Well, if you really think that’s important, be my guest."
A classmate's sexuality, he added, was the "furthest thing" from his mind at the time.
ABC News reported that the Romney campaign was reaching out to other old high school pals on Thursday, asking them to come forward with "supporting remarks."
But the hits just kept on coming for the Romney campaign, as video emerged of another former classmate remembering him not so fondly.
"I have to say that I've had trouble taking him seriously as a candidate because I have this memory of him as a 14-year-old boy who was kind of a jerk, the way most 14-year-old boys are, including myself," conservative pundit Michael Barone, now a fellow at the American Enterprise Institute, said at a recent event.
The bullying revelations come on the heels of another story from Romney's past that's caused him trouble on the campaign trail — his treatment of the family Irish setter.
In 1983, Romney strapped the dog to the roof of the family station wagon in a kennel during a 12-hour road trip to Grand Bend, Ont. When Seamus suffered intestinal distress, Romney stopped the car, hosed him off at a service station, returned him to the crate and kept driving.
"No wonder the story of poor Seamus on the roof of the car never goes away: we have stories of Mechanical Mitt, and Mean Mitt, and very few of Mitt as a man who shows genuine empathy to people (or other living beings) less powerful than he is," Salon.com's Joan Walsh wrote in a piece entitled Mitt, The Prep-School Sadist.
Romney was never punished for the '65 incident, the Post reported.
Lauber, who reportedly remained traumatized by the attack for years afterward, was "a soft-spoken new student one year behind Romney … walking around the all-boys school with bleached-blond hair that draped over one eye," the Post reported.
Romney rounded up some friends, including Matthew Friedemann, who's quoted liberally in the story.
"They came upon Lauber, tackled him and pinned him to the ground. As Lauber, his eyes filling with tears, screamed for help, Romney repeatedly clipped his hair with a pair of scissors," the Post reported.
The boy disappeared from school for a few days after the attack, returning with his cropped hair back to its natural brunette hue, the Post reported. He was later kicked out of the school for smoking a cigarette.
When a witness to the attack ran into Lauber years later in Chicago, he was still shaken by it.
"It was horrible," Lauber reportedly told David Seed, a witness to the event, who apologized to him for not stepping in to stop it. Lauber died in 2004.
That's not the only troubling incident recounted by Romney classmates in the Post story. He also allegedly said "atta girl" to a closeted gay student, and deliberately held a door closed while a vision-impaired teacher strolled into it.
The revelations, detailed by witnesses who say they now lean Democrat, spurred a national political debate: Are they relevant?
Liberals, predictably, believe they provide a glimpse into Romney's soul.
Romney "was intolerant in 1965, assaulting a presumed homosexual with scissors, and he's intolerant today opposing civil unions" and same-sex marriage, tweeted Brad Woodhouse, chairman of the Democratic National Committee.
Conservatives, on the other hand, were dismissive and accused the media of failing to delve into Obama's past in a similar manner.
"The Washington Post can't be bothered to worry about Barack Obama's college years, college transcripts, communist friends, cocaine use, or cop-killing plotters in whose living room he first launched his major political career," wrote Erick Erickson, a frequent CNN panelist and managing editor of RedState.com.
"But they can get in the really-way-back machine to 1965 and Mitt Romney's high school years."
Patrick Egan, assistant politics professor at New York University, said stories about Romney's high school misdeeds or a young Obama in love — detailed in the current issue of Vanity Fair — ultimately don't mean much.
"Certainly, none of it is very relevant at all regarding how either of them govern now," he said.
"They certainly will colour impressions, and in Romney's case, they reinforce what some voters don't like about him. But what happens with these stories is people look to them to bolster what they already believe about a candidate. They don't often change anyone's minds."