Pence and the Giants finalized a $90 million, five-year contract, the team announced Sunday.
"I can't say too much until it's official," Giants manager Bruce Bochy said. "It's good news. I couldn't be happier for Hunter."
The 30-year-old Pence politely declined comment.
He had been eligible to become a free agent after the World Series.
"You can't help but love Hunter Pence and the way he plays the game," Bochy said. "It's all about making a commitment and getting back on track. You need great players."
"He's a very positive man," Giants outfielder Angel Pagan said. "The game could be 20-0 with two outs in the ninth, and he still thinks we can win it."
Pence is batting .282 with a career-high 26 home runs and 94 RBIs. He received the Willie Mac Award on Friday night, given to the most inspirational member of the Giants.
He's played in every game this season and would become the first Giants player to play every game since Alvin Dark started all 154 games in 1954. The last outfielder to play in every Giants game was Bobby Thomson in 1949.
The two-time All-Star outfielder was acquired from Philadelphia in July last year and was credited with being instrumental in San Francisco's second World Series title in three years.
"We're here not just to play baseball, we're here to win," Pagan said. "This is good news for us. It's good he stays here. We know the type of team we've got."
The right fielder leads the NL with 369 putouts. He has an 88 percent success rate in stolen bases and is third with 298 total bases. Pence ranks sixth in hits and fourth in doubles.
Pence finished third in NL Rookie of the Year voting with the Houston Astros in 2007.