BY BERNIE MIKLASZ, Post-Dispatch Sports Columnist

DALLAS • One is a former toll-booth attendant who used to clean the bathrooms and sweep the floors of his father's blue-collar neighborhood saloon. For all of his fancy offense and brilliant play-calling, Green Bay coach Mike McCarthy is just a working-class kid from the outskirts of Pittsburgh.

The other head coach is a closet intellectual who used to conceal his perfect grades from teammates during his childhood near Newport News, Va. Mike Tomlin didn't want anyone to get confused and assume that he lacked toughness. So when his mother put a "Proud Mother of Honor Roll Student" bumper sticker on the family car, Tomlin promptly tore it off.

"He didn't want anybody to know he was a 'brain' in high school," said Tomlin's mother, Julia Copeland. "He wanted to be a regular football player like everyone else. He didn't want the other players to call him a nerd. He kept it quiet, but in his junior year he made straight A's and they put his name in the newspaper. So he couldn't keep it hidden."

And Tomlin probably gave himself away later on in life by quoting from a Robert Frost poem moments after leading Pittsburgh to the AFC championship two seasons ago.

As they say, looks can be deceiving.

The coaches for Super Bowl XLV can attest to that.

McCarthy was supposedly the one-dimensional offensive mind who stunned Green Bay by scrapping the team's defense and starting over with a 3-4 alignment after the 2008 season. (Defense? What does McCarthy know about defense?) The Packers finished No. 2 in the NFL in fewest points allowed this season.

And the guy who coaches Vince Lombardi's franchise has a little more in common with Lombardi than you'd think.

"What made Lombardi so great was his legendary dedication to seeking perfection," said former Rams assistant head coach Rick Venturi, a friend of McCarthy from their time together on the same staff in New Orleans. "But that just didn't happen. It took a lot of hard work. Mike is like that in that he's just consumed with the game. He has that single-minded purpose. He's a street kid, a tough Pittsburgh kid, a throwback guy. If you want something in life, you grind away and work for it. That's Mike."

Make no mistake, Tomlin is legitimately tough. When he replaced the retired Bill Cowher in 2007, Tomlin put the Steelers through a brutal training camp, just to remind everyone that a new boss was in charge. But as soon as he had the players' attention, Tomlin adapted.

"Mike Tomlin was very militant when he came here," Steelers wide receiver Hines Ward said Monday. "He wanted to see who would challenge his authority and he got rid of some of the guys that questioned it a little bit. He kept the guys that followed what he wanted. Once he got a full year or two, then he let up a little bit.

"And this gradually became his team. He checks on his players every day. He wants to make sure we're OK. He is very good at taking the temperature of this team. I think guys love playing for him. He's just a pro's coach and he stands up for everybody."

As a kid, Tomlin built models of vast cities made out of Legos or Lincoln logs. He was a member of the National Honor Society. He would later graduate from the prestigious William & Mary University — not exactly a football mill. In high school, Tomlin competed (with several other students) in an academic competition called "Odyssey of the Mind" and finished second in the state. As a player, Tomlin kept meticulous records of every meeting and practice in a Franklin planner.

"He never missed a detail," Tomlin's mother said. "He had a plan for everything."

Including success, apparently.

Tomlin became an NFL head coach at age 34. He won a Super Bowl at age 36. If the Steelers defeat the Packers, Tomlin would be the youngest coach to win two Super Bowls. And the only coach in NFL history to have two Super Bowl wins in his first four seasons. Chuck Noll, who coached the Steelers to four Super Bowl titles in the 1970s, didn't win his second Super Bowl until age 38.

In other fields, he would be called a "prodigy." Whether he likes it or not, Tomlin will have to accept that the football world views him as one of the smartest coaches around. That's why the Rooney family hired him in '07 despite his relative inexperience, with only one season as a defensive coordinator on his NFL résumé. There was something special about Tomlin. The Rooneys knew it. And his subsequent record in Pittsburgh proves it.

If observers saw Tomlin's surface toughness and didn't take note of his abundant intelligence, McCarthy probably experienced the reverse perception. On the way up, he was viewed as the cerebral aficionado of the West Coast offense. That reputation helped get him the gig as Green Bay's head coach in 2006.

What got overlooked was McCarthy's iron constitution. He paid plenty of dues along the way, working as an unpaid assistant at the University of Pittsburgh, where the staff included future NFL head coaches Jon Gruden and Marvin Lewis. And then there was a job in Kansas City, where he learned a few things from an old classic quarterback named Joe Montana. McCarthy made other stops as an assistant — Green Bay, New Orleans, San Francisco — before being given the top job with the Packers.

And did McCarthy really work in a toll booth? Yes. He wasn't getting paid at Pitt and had to do something about his bills. That's why he also cleaned the bathrooms at his father's place — Joe McCarthy's Bar & Grill.

"And after a Saturday night, I probably don't have to tell you what the bathrooms looked like," McCarthy said. "I collected tolls on the Pennsylvania Turnpike. It was a summer job. It didn't pay much. But it was a good experience. I studied when I was there, when there were no cars coming up to the toll booth. I'm glad I took that path as a young man, having these type of experiences."

McCarthy didn't finish the thought, but he didn't have to. The message was obvious: He's earned everything he has, including this chance to win a Super Bowl. No one handed him anything. And it takes a tough man to say no to Brett Favre and stick with his decision to go with the untested Aaron Rodgers at quarterback in 2008, after Favre rescinded his retirement.

This is an appealing matchup of two coaches who were widely underestimated when they became head coaches.

Tomlin and McCarthy have learned a lot, albeit in different places — whether it be William & Mary or the bar & grill. But the coaches have arrived at the same place, Super Bowl XLV.