Now he's all but guaranteed to have the second-longest coaching tenure for the storied franchise behind Tom Landry, the only coach the Cowboys knew for their first 29 years.
Garrett has a new five-year contract, and defensive co-ordinator Rod Marinelli is also coming back on a three-year deal, a person with knowledge of both agreements told The Associated Press on Tuesday. The person spoke on condition of anonymity because the team had yet to announce the deals.
Garrett will make about $6 million annually — roughly $30 million in total value — after just completing his first contract, at four years and $20 million.
The Cowboys broke through a three-year rut of 8-8 seasons that ended with losses that kept them out of the playoffs by winning the NFC East at 12-4. Dallas beat Detroit in the wild-card round before last weekend's 26-21 divisional round loss at Green Bay.
"I really believe that we've built something here that we're all proud of and we're all excited about taking the next step with this football team," Garrett said earlier Tuesday, before the deals were settled.
"I think we have the right kind of guys on our staff, the right kind of guys on our team and we're excited about the opportunities and the challenges ahead."
The 48-year-old Garrett, a former backup on Dallas' Super Bowl-winning teams of the 1990s, is 42-32 in four-plus seasons and needs two victories to tie his old coach, Jimmy Johnson, for second on the franchise wins list. Landry is third all-time in the NFL with 250 victories.
When he finishes the first year of his new contract, Garrett will have coached the Cowboys longer than Johnson, who won consecutive Super Bowls after the 1992 and '93 seasons. Landry also won two titles.
Marinelli replaced Monte Kiffin as defensive co-ordinator before this season — a year after they came in together to install a four-man defensive front after Dallas spent nearly a decade in a 3-4 formation. The Cowboys improved from the league's worst defence to 19th along with being second in takeaways.
There were suggestions that he might join the staff of good friend Lovie Smith in Tampa Bay. They were together in Chicago before Smith was fired and Marinelli picked a demotion to defensive line coach with the Cowboys over staying with the Bears as defensive co-ordinator.
Dallas was competitive defensively despite the loss of linebacker Sean Lee to a knee injury in the first off-season practice and constant change at that position because of other injuries.
"He made our players better. He made our coaches better," Garrett said of the 65-year-old Marinelli, the former Detroit coach and a candidate for NFL assistant coach of the year. "I thought the defence played remarkably well."
The Cowboys also have expiring contracts with dynamic receiver Dez Bryant, NFL rushing leader DeMarco Murray and the man who engineered that offence, play-caller Scott Linehan.
In his first season with Dallas, Linehan struck up a strong relationship with quarterback Tony Romo right away, and helped produce Romo's most efficient season and the best rushing total in franchise history, breaking a mark set by all-time NFL rushing leader Emmitt Smith.
The former coach in St. Louis, Linehan has surfaced as a potential candidate for several of those openings around the league. He was the offensive co-ordinator for five years in Detroit before coming to Dallas, and spent a year with Garrett on the Miami staff about a decade ago.
"Came in here with a system of football that was in place with a lot of players and coaches that were in place and fit himself in and led that offensive unit really, really well," Garrett said. "Like with Rod, I learn a lot from these guys on a daily basis."
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