Romo signed a six-year contract extension worth $108 million Friday, with about half of that guaranteed to make him the highest-paid player in franchise history.
The agreement, reported on the team's website, will lower the quarterback's salary cap number for 2013 by about $5 million, giving the team more room to sign free agents and draft picks.
Romo, who turns 33 next month and was entering the final year of his contract, gets $55 million guaranteed.
Super Bowl winner Joe Flacco got $52 million guaranteed in the six-year, $120.6 million contract he signed with Baltimore earlier this month.
"I think it's just exciting more than anything that you know you're going to be here the rest of my career," Romo said in a video on the team's website that showed owner Jerry Jones exchanging high-fives with Romo's nearly 1-year-old son. "We're a team on the rise and I think it's going to show here going forward."
Romo could be with Dallas through 2019, giving him a chance to be the starter longer than the 11 seasons of Aikman and seven of Staubach, who was a part-time starter his first four years with the Cowboys.
Aikman and Staubach won five Super Bowls between them, while Romo has just one playoff win in six full seasons as the starter. He had a gut-wrenching playoff loss the year he took over midseason in 2006, flubbing the hold after driving the Cowboys into position for the go-ahead field goal in the final minutes.
Romo alluded to changes "behind the scenes" in the interview on the team's website, and Jones said in a statement that his quarterback will have "a significant level of input and contribution to the planning and implementing of our offensive approach — both in the meeting room and on the field."
"Tony is uniquely qualified to lead this team at the quarterback position for the next several years," Jones said. "He knows how to run an offence and run a team."
Romo lost playoff-or-bust games in regular-season finales the past two years. That included a loss to Washington last season when Romo threw an interception with a chance to tie or win the game with a drive in the final 3 minutes.
A former Romo rival, Donovan McNabb, questioned the deal on Twitter.
"Wow really, with one playoff win," McNabb wrote. "You got to be kidding me."
Dez Bryant, who teamed with Romo for career highs of 1,382 receiving yards and 12 touchdowns in 2012, tweeted, "Congrats Big Tony on the contract extension."
Romo is the franchise leader in touchdown passes and the single-season leader in touchdowns, passing yards, completions and attempts. He had a career-high 4,903 passing yards in 2012 but matched his highest interception total at 19 and had his lowest quarterback rating at 90.5 rating.
His best rating of 102.5 came in 2011, when the Cowboys lost to the New York Giants with a playoff berth on the line in the finale. His other best season was 2009, which included his only playoff win against Philadelphia.