Two of those homers and five RBIs came in last year's NL division series against the Reds, when San Francisco became the first team in big league history to rally from a 2-0 deficit to win a five-game series with three straight road victories.
"We've got a group of guys who are not going to rest on what we've accomplished so far," Posey said. "Nine years is a long time. It's exciting. I enjoy the challenge of trying to get better. I enjoy the ups and downs that baseball brings."
On May 25, 2011, Posey tore three ligaments in his left ankle and broke a bone in his lower leg in a devastating collision at the plate with Scott Cousins, then with the Marlins.
Posey received his nice payday two days after turning 26. He will donate $50,000 per year to Giants charities.
He could wind up playing his entire career in the Bay Area — and the Giants certainly hope that will be the case. The club posted a photo on its Twitter account Friday of Posey, Baer, Sabean, vice president and assistant general manager Bobby Evans and Bochy — with the hashtag "SFG4Life."
"It's truly one of the great days for Giants fans," Baer said. "Our fans will be very privileged to watch Buster for the foreseeable future, and ideally Buster will be wearing a Giants uniform for the entirety of his career, which is our goal."
Posey is represented by the same agency that negotiated Cain's deal last year, and both sides were eager to do something again this year to provide long-term security for the catcher.
"We're extremely pleased to reach an agreement that keeps Buster in a Giants uniform for a long time," agent Jeff Berry of CAA Baseball said. "Buster and the Giants have brought each other mutual success, and this contract reflects Buster's extraordinary accomplishments in just three years in the major leagues."
The contract includes the following bonuses: $100,000 for NL MVP, $100,000 for World Series MVP, $75,000 for NL championship series MVP, $50,000 for a Gold Glove, $50,000 for All-Star game election, $25,000 for All-Star selection and $50,000 for a Silver Slugger.
In 2010, Posey wasn't even called up from Triple-A Fresno until late May but still batted .305 with 18 home runs and 67 RBIs in 108 games to help the Giants capture their first NL West crown since 2003.
Even with the injury, Posey plans to catch for as long as his body allows it.
"My passion is to be behind the plate for as long as I can," he said. "For anyone who's caught, it's a special position you can't describe until you get back there."
Yet he did once play all nine positions in one game during college.
San Francisco gave him $6.2 million when he signed in August 2008 as the fifth overall pick out of Florida State, the richest deal for an amateur joining the Giants.
For Evans in his negotiations, there weren't many players to use as a gauge for having so many accomplishments in such a short career. The Giants entered talks with the idea they would find a way to sign Posey for the long haul.
"The organization will be better off for it each day he's in our uniform," Sabean said.
AP Sports Writer Ronald Blum contributed to this report.