By last summer, he'd worked his way up to being the promising backup.
Now Romo is the marquee attraction, the Pro Bowler whose love life recently was examined by National Enquirer and the guy whom Jerry Jones has singled out as the key to the team's success.
Big change, right?
Nope, Romo insists.
"I try to come out here and be as good as I can be," he said at the start of training camp. "Whatever that is, I don't know."
Nor do the Cowboys. They hope he'll be the quarterback who won five of his first six starts, beating the eventual Super Bowl champion Colts when they were 9-0 and throwing five touchdown passes against Tampa Bay on Thanksgiving. But they have to be wary of the player who finished 1-4, capped by botching the hold on a short go-ahead field goal attempt, knocking Dallas out of the playoffs in the first round.
Romo's flub, and his teary locker room apology, was a dramatic end to a breakout season that at times seemed too good to be true. He got to enjoy some of the spoils of success over the summer - the Pro Bowl in Hawaii, judging the Miss Universe pageant, dating country singer Carrie Underwood - but is now serious about getting back to work.
After all, he's the starter. This is his team.
So when he hears his boss, Jones, say the onus is on him to play well if the Cowboys are going to reach their goals, Romo agrees. He knows quarterbacks will always face that pressure.
"Guys are going to look to you," said Romo, who hasn't gone into a season in this role since 2002, when he was a senior at Eastern Illinois. "No matter what you've done, you've got to go out and perform. You've got to win ballgames. You're playing for a Super Bowl. If you're not, there is no reason to play the game."
"You work hard so you can improve," he said. "I feel like I have, but we'll see when the time comes."
Another time that's coming is contract negotiations.
Romo is in the final year of a deal signed last summer. He receives a $1 million salary on top of a $2 million signing bonus, making him one of the cheapest starters in the league. By comparison, Houston gave highly touted but unproven Matt Schaub a $48 million, six-year deal.
The question facing Romo and the Cowboys is whether to sign now or let him play out this season to better gauge how much he's worth.
Will Romo risk sacrificing the security of money in the bank now in hopes of a lot more later? Then again, how much security would the team give a quarterback with only 11 career starts?
The two sides have started to exchange numbers and ideas. The Cowboys are willing to do some creative structuring, but they also know they have the luxury of time. At worst, they could always keep him by using their franchise designation, although it's something club officials proudly say they've never used.
"If the conditions were right, then I could be real happy before the season starts," Jones said. "If it's the other way, I can make that work. ... You know, we pay guys that play. We really pay them when they play good enough to win Super Bowls."
Romo is trying to play it cool, saying he's lucky to get paid for the game he loves and that discussing his salary "takes away from the purity of it."
"It doesn't change my outlook," he said. "I am going to work and do everything I can to help this football team win. As long as I am the quarterback here, that is what I am going to do, no matter what money says."
Well, there is one thing he's not going to do - be the holder. That job now belongs to his backup, Brad Johnson.
"I think," Romo said, "my holding days are done."