The pregame ceremony was attended by his wife, Kristin, and his parents along with the five previous Giants Rookies of the Year: Willie Mays (1951), Orlando Cepeda (1958), Willie McCovey (1959), Gary Matthews (1973) and John Montefusco (1975).
"These are a special group of guys," Posey said of his teammates. "They make it fun to come to the ballpark every day. I'm fortunate to play with guys who play the game with so much passion. I want to thank the coaching staff, the scouting staff and the training staff who gives us every opportunity to succeed."
Posey, who edged Atlanta's Jason Heyward for the award, hit .305 with 18 home runs and drove in 67 runs in 108 games to help the Giants win their first World Series title in San Francisco and the first in franchise history since 1954.
"Most importantly I want to thank my wife, Kristin, for her unconditional love and support," Posey said, "and for being there for me after good games and being there after not-so-good games."
Posey then turned to the group of former Rookie of the Year honorees and thanked them for attending the ceremony.
"I'm very humbled to be in your presence," he told them.
Montefusco said he's rooting for Brandon Belt to win the award this season.
"It would mean I get to come back again next year," he said. "I'm out in New Jersey. I love coming back. I hope Tim Lincecum and Matt Cain throw a no-hitter, so I can come back out again."
BBWAA chapter president Jorge Ortiz, of USA Today and formerly of the San Francisco Chronicle, presented Posey with the writers award while Cain, with the rest of the team surrounding Posey, presenting him with the players' award.
"He's getting well-deserved awards," Giants manager Bruce Bochy said. "It's enjoyable to see him get them."