Edwards said he has no plans to race again, but he added that he wouldn't use the word "retirement." He said the timing was right to leave now -- that he is satisfied with his career and the schedule is grueling.
Dale Earnhardt Jr.'s battle with concussions did affect Edwards' decision, he said.
"It's a risky sport," Edwards said. "I am aware of the risks. I don't like how it feels to take the hits that we take. I'm a sharp guy, and I want to be a sharp guy in 30 years. Those risks are something that I want to minimize. ... Like anybody in a contact sport, I realize that there might be long-term consequences to that stuff. That is a piece of the puzzle [on the decision]."
Edwards will be replaced by Daniel Suarez, the first full-time Mexican-born driver in the Monster Energy NASCAR Cup Series.
The 37-year-old Edwards spent the past two years at JGR and had one year remaining on his deal.
"I can't come up with a good reason why now isn't a good time [to stop racing]. ... I'm not going to say this whole thing was easy or clean or perfect," said Edwards, who owns a farm and said he also could be interested in broadcasting. "There was no epiphany moment. This has been something that I really thought a lot about. Part of me went back and forth."
NASCAR chairman and CEO Brian France issued a statement after Edwards' announcement.
"Carl Edwards has made an indelible mark on NASCAR," he said. "His hard-charging driving style has led to memorable moments that will live forever in the history of our sport. Carl's passion and personality will greatly be missed -- as will the signature backflips that NASCAR fans have come to expect following his victories. We wish Carl nothing but the best as he enters this next phase in life."
Edwards had a shot at the championship in each of the past two years. He failed to make the championship round in 2015, when rain shortened the race at Phoenix. He was one of the four finalists in 2016 and was leading the championship contenders when trying to block on a restart with 10 laps remaining in the finale at Homestead.
He won 28 races in 445 career starts, including three times in 2016. He spent the bulk of his career at Roush Fenway Racing, where he replaced Jeff Burton in the No. 99 car in the 2004 season and quickly climbed up the NASCAR ladder.
He finished second in the standings in 2008 and again in 2011, when he engaged in an epic battle with Tony Stewart. Stewart's five wins -- including a victory at Homestead where Stewart and Edwards went 1-2 -- earned him the championship over the one-win Edwards.
"I am personally satisfied with my career. ... You guys know I don't race just for the trophies," Edwards said. "This has been a neat journey for me. I've been rewarded by the challenge."
Edwards never missed a Cup race because of injury and was consistently considered among the most fit athletes in racing. He reiterated he is healthy, but he understands the long-term health risks of racing. He added that everyone in his family is healthy.
He stressed that he did not make this decision to move to another team.
"If I am going to get back in a race car, I'm calling Coach [Joe] Gibbs first," he said. "There is no better race team. ... I don't have any intention going back to full-time racing. I don't have a plan to drive a race car right now. But I know how things work - if it comes up and the right opportunity is there and it is the right thing, for sure I would entertain it."
Both Edwards and Gibbs said the decision did not stem from any heated contract negotiations. Edwards also said the decision was not made out of any frustrations with NASCAR.
"This had nothing to do with any contract negotiations or anything like that," Edwards said "This is not a money deal. ... If I was looking for a sure bet to make a living, I would not have picked racing."
Edwards told Gibbs just before the holidays, and Gibbs told him to take four days to think about it. During their follow-up conversation, Gibbs was convinced that Edwards felt good about the decision.
"Honestly, it was a total shock," Gibbs said. "I could tell in his face that it was something he had really thought about. He was kind of emotional and it was something he felt like he needed to do. I sat there and looked at him and said: Look, let's take some time here because if we start down this path, there's not a turning back on this. ... Out of anybody in our NASCAR world, he's his own man."
Crew chief Dave Rogers tried to be philosophical about the change after coming so close with Edwards in winning the title. He said the what-the-heck-just-happened feel in losing the title with a race-ending crash and the shock of the Edwards decision were different.
"At the end of the day, it's a game," Rogers said. "But the game is played with people. And we care about all our people here and we have a tight-knit team. So when Carl said, 'Hey, I think we have to do something different' -- it's different. It's not a game, it's life and it's someone I really care for. ... When Carl broke this to me, it was a true sympathy for him and what he was going through and trying to understand what he was feeling to come to this decision."