The six-year contract is worth $84 million and $40 million guaranteed, Rapoport reported Wednesday. The deal includes the largest guaranteed salary for the position.
Martin has established himself as one of the best in the NFL at his position, earning a Pro Bowl selection in each of his first four seasons. He was named first-team All-Pro twice in this stretch, adding two more selections to the second team.
Pro Football Focus rated him as the No. 3 offensive guard in the league in 2016 and No. 2 overall in 2017 behind only David DeCastro of the Pittsburgh Steelers. He has especially excelled as a run-blocker, ranking as the top player at his position in the ground game.
Additionally, he has started all 64 regular-season and three playoff games for the Cowboys in his time in the league.
This skill set and durability are a big reason the organization was determined to sign him to a long-term contract.
"I think he's an important part of our future," Cowboys executive vice president Stephen Jones said in July of 2017, per Rob Phillips of the team's official website. "He represents everything we want our players to be about. He's not only a great player on the field, he's a great person off the field."
Although the two sides weren't able to come together on a deal prior to last season, the player remained confident in finding a long-term deal.
"I was lucky enough to be drafted here and I want to be here for my career," Martin said in December, per Brandon George of the Dallas Morning News. "Hopefully we can get something worked out."
They were finally able to come to an agreement, keeping intact one of the top offensive lines in the NFL that also features Pro Bowlers Tyron Smith and Travis Frederick. Although the team took a step back in 2017 while finishing with a 9-7 record, there is enough talent available to return to prominence in 2018.
With young stars like Dak Prescott and Ezekiel Elliott still playing under their rookie contracts for the next few years, Dallas could remain a top contender in the NFC for several seasons.