Alex Mack is the guy who’s always smiling.

After playing seven seasons in Cleveland, Mack, a three-time Pro Bowl center, signed with the Falcons in free agency and has helped lead a dazzling turnaround of the offense.

“Life is good,” Mack acknowledged.

The Falcons (7-4), who are in first place in the NFC South, are set to play the stout Kansas City Chiefs (8-3) at 1 p.m. Sunday at the Georgia Dome.

With the center position stabilized, the offense is on pace to score 521 points, which would shatter the franchise record of 442 that was set in 1998, the season the Falcons finished 14-2 and went to the Super Bowl.

“We are right there in the hunt,” Mack said. “We just have to keep focusing on each day and get better and see if we can finish out the season right.”

One of the keys to the Falcons’ turnaround has been the stability that Mack has provided. There are no concerns about errant shotgun snaps, and he’s helped elevate the players around him.

“Playing that center position, he’s in charge of all the calls and everything,” left tackle Jake Matthews said. “He gets everything going when we get up to the line of scrimmage.”

Mack is the only new starter along the offensive line, which struggled at times last season in picking up all of the calls. He blended in quickly with his new team.

“You could tell from the first day that he came here, from just the way that when we were in meetings the questions that he asked,” Matthews said. “He makes you think about things in a different way. That’s been really beneficial for us. It’s made us all grow and have a better understanding of the offense.”

Mack’s reputation preceded his arrival.

“Alex came in, and we all knew what kind of player he was,” right guard Chris Chester said. “He just came in and was ready to learn and be a part of what we were building here.”

Right tackle Ryan Schraeder is a big Mack supporter, too.

“Alex has been huge for us this year,” Schraeder said. “He’s really solidified that inside with communication and with the way he works. The way he gets after people. He’s relentless. He’s everything you want in a center.”

Mack, who played in the Falcons’ offense while in Cleveland under offensive coordinator Kyle Shanahan in 2014, didn’t force his will on the offensive linemen.

“He was still his own man, but he didn’t come in and try to change everything to make it his way,” Matthews said. “We all have a really good idea of what we want to be and what we want to accomplish. He’s brought into everything. He’s been a really good teammate in that regard.”

Mack respected the Cleveland fans’ love of the game. But the football operation was faulty, and he wanted out.

Mack talked with quarterback Matt Ryan during the Super Bowl week in San Francisco, and the two hit it off. Mack signed a five-year, $47.5 million deal with the Falcons on March 9.

“I think I assimilated really well,” Mack said. “They are a good group of line guys. They all work hard. It really didn’t take much work. I just jumped right in, and I was myself. They kind of accepted me, and I blended in that way.”

It was a disaster watching Ryan jump around trying to get to shotgun snaps from Mike Person and James Stone last season. There were times when the ball was rolled back to the quarterback.

“It’s good because it’s something that we talk about all the time,” left guard Andy Levitre said. “Our program revolves around the ball, and we want to make sure that we take care of it at all times on offense. I think he’s done a good job of handling it.”

The simple center-to-quarterback exchange hasn’t been an issue with Mack.

“Alex has been great for us,” Ryan said.

Ryan believes the addition of Mack and the continuity of the unit has helped.

Mack is helping the line get ready to face Kansas City’s stout front seven that features the dynamic Justin Houston, a former standout at the University of Georgia.

“Kansas City likes to line up and do their thing,” Mack said. “They run kind of the same front, and they are little bit more disciplined.”

Schraeder knows that Mack will have some tips to help everyone get ready for the Chiefs.

“I would say the biggest thing is probably the run game, getting that going,” Schraeder said. “Coming off the ball and getting after these guys. The best pass block is a run block.”

Every play starts with a snap, and that’s no longer an issue for the Falcons.