Ross, 33, is making $1.6 million in the final season of a two-year, $3 million deal and was eligible to become a free agent after this season.
"He deserves it," said manager Bobby Cox. "He's a real good catcher, he hits, too, and he's about the greatest teammate anybody could ever have."
Added general manager Frank Wren: "Not only is [Ross] a top-notch backup, and he's one of the very best, but he's also a big part of our team and a big part of our team chemistry -- that group of guys on our bench that have strong leadership capabilities. Guys listen to him and guys rally around him. He brings a lot to the table."
McCann is also signed through 2012, with a club option for 2013. Ross' extension ensures that the Braves' young pitchers will get to work with the same receivers going forward and creates an air of stability.
"I just get to sit back and watch [McCann] do his thing and be there for an emergency," Ross said. "We have a pitching staff that's amazing here and a starting catcher who's unbelievable, and I think they just shored up insurance, basically. I feel like I'm a good insurance policy if anything goes down. They trust me with the pitching staff that they've invested a lot of money in and some great pitchers on the way up who have already proven themselves over the last year, year and a half."
Wren said that the extension had been in the works for "nearly a month," though Ross said negotiations intensified over the past week.
"We had talked in June about his desire to come back and our desire to keep him," Wren said. "When there's a desire on both sides to get something done, it can happen pretty quickly."
Ross is batting .269 with 18 RBIs in 35 games (21 starts) this season, his second with the Braves and ninth in the Major Leagues.
"When you're a bench player or a role player, an extension in the middle of the year is kind of like a dream come true," Ross said. "You don't ever expect that. Role players don't usually get that opportunity, and it's one of those things you dream about and hope for. Especially a two-year extension, [because] it gets me to 10 years [of service time] and it's a huge, huge thing."