Walls has been a season ticket holder since 1994, and has missed just one Braves home game since then.
"I've missed one home game back in '98, and that's because it was my grandmother and her twin sister's 90th birthday," Walls said.
To date, he has attended 1,111 consecutive home games and almost 2,000 in all.
So why is he so passionate? Walls, a man of few words, says he simply just likes to show encouragement for his favorite club.
"I'm from here. I want to support my hometown team," Walls said.
As he walks the Turner Field plaza hours before each first pitch, Walls poses for pictures and strikes up conversations with the fans around him, becoming almost an unofficial team mascot.
"What I like about Bob is he's always sociable," Foston said. "He's always willing to stop and take a picture with someone."
Walls has little choice -- his costume draws the attention of everyone around him. If his tan shirt and pants with intricate designs along the sides don't grab you, maybe his headdress will. Blue, red and white feathers protrude from a headband with "Braves" emblazoned in red paint on the front.
"It's pretty special," Walls says. "It's pretty fun to come out and do what I do."
Walls embraces his role, and always takes time to talk with fans before taking to his seat in section 135.
"You get used to a routine. You get used to seeing season-ticket holders," Foston said. "Bob wearing the outfit, it kind of makes it complete. When we come out and settle into our roles, that's Bob's role."
His favorite game? That's easy, says Walls. Despite the hundreds of games he's witnessed, Brooks Conrad's heroics against the Reds last season stands out above the rest.
"My most memorable game was last year when the Braves were down, 9-3, and scored seven runs to win on a walk-off grand slam," Walls said with a smile.
Other moments have come close, though. He says Eric Hinske's dramatic eighth-inning homer against the Giants in last season's National League Division Series landed about eight feet away from him.
Walls enjoyed the playoff games in 2005, after a 14-year post-season drought. But his support never wavered regardless off the team's success.
"It was real special being here during all those years," Walls said. "I knew there were going to be some ups and downs, and I knew they weren't going to win the division every year, but I wanted to support them the best way I can."
Walls, who suffers from a learning disability, will play tennis in this weekend's Special Olympics at Emory University in Atlanta. He also plays second base and bats leadoff for his softball team in the fall.
Happily for Walls, the Braves open Interleague Play on Friday at the Angels, so he won't miss a home game during the Special Olympics. But when the team returns to face the Reds on May 27, "The Chief" will be there.