Favre, who previously avoided talking publicly about his ending in Green Bay, made his comments during a radio interview with WGR 550-AM in Buffalo on Thursday.
"It's over and done with. I was at fault," Favre said. "I feel that both sides had a part in it. If you could go back, would I or them have done things differently? I'm sure both sides would. But you can't."
One of the most beloved players in franchise history at one time, Favre made a regular habit of contemplating retirement after each season late in his career. He did retire after the 2007 season, but that offseason he unretired (in July 2008). However, the Packers already had moved forward with Aaron Rodgers as their quarterback of the future.
Favre decided to report to training camp with the team in 2008, causing a rift with the organization, Rodgers and the club's rabid fan base. The Packers ultimately decided to trade Favre to the New York Jets. After one season with the Jets, Favre went on to play two seasons for the NFC North rival Minnesota Vikings, getting booed in his return to Lambeau Field.
In February, Rodgers said it was "time to heal things up" and "move forward" with his relationship with Favre. The duo appeared together at the NFL Honor awards show, a moment Favre called pivotal in their relationship.
"Aaron has said some very nice things. He and I have a good relationship," Favre said. "I had a chance to present an award with him at the Super Bowl and that was for real. It wasn't for show. And so I think everything will be fine."
Packers president Mark Murphy also said in March that he wanted Favre "back in the family" and that a Favre jersey retirement ceremony would happen in the future.
Favre on Thursday did relent from a previous stance when he said he didn't need a retirement ceremony.
"I don't know of any player who would not want that to happen," Favre said of having his number being retired. "I'm honored just by the thought. Obviously there was, if you want to call it, 'bad blood' or whatever. I just think that people started picking sides. And really I'm over that and have been over it."
During the interview, Favre also credited Murphy for saving his relationship with Rodgers and the organization. Murphy became the club's president in December 2007, months before the Favre drama began.
"[Mark] kind of came into a hornet's nest [in 2007], if you will," Favre said. "He's been extremely great in trying to make this work. In our discussions, [the retirement ceremony] will happen. I think both sides are genuine. I know they are. And that's the way it has to come across because that's the way it should be. We don't want to go out there waving to the crowd with our backs to each other. And I don't think that's going to happen."
Last September, on the "Monday Night Football" podcast hosted by ESPN's Mike Tirico, Favre said he had begun to get over any hard feelings he held toward the organization, with which he won three MVP awards and a Super Bowl title.
"I think in some ways that has happened. … Even though it's a shame the way things went down between I and the Packers, as time goes by, it's like a grudge … you just kind of get over it, you know?" Favre said.
Information from ESPN.com NFC North blogger Kevin Seifert was used in this report.