1977 Dallas Cowboys season

Their 15–2 (.882) record (including the postseason) remains the highest single-season winning percentage in franchise history.

The Cowboys became the 4th team in NFL history to win two Super Bowls, joining the Packers, Dolphins, and Steelers.

[1][2] To improve their running game, the Cowboys orchestrated a big trade with the Seattle Seahawks, moving up in the NFL draft to acquire running back Tony Dorsett, the Heisman Trophy winner from national champion Pittsburgh.

[3] With the retirement of Lee Roy Jordan, Bob Breunig became the starting middle linebacker, Randy White was moved to defensive tackle, and Thomas Henderson became a starter at strongside linebacker, turning the defense into a dominant unit.

With an improved offense and defense, the Cowboys finished with a 12–2 regular season record, breezing through the playoffs by beating the Chicago Bears 37–7 in the divisional round, defeating the Minnesota Vikings 23–6 in the NFC Championship Game and winning Super Bowl XII 27–10 against the Denver Broncos.

In a 14-game season he totaled 85 tackles and an estimated league-leading 23 sacks[5] (more than Michael Strahan's 22.5 record in 16 games), he was named the NFL Defensive Player of the Year, a consensus All-Pro selection, was a key player in the Cowboys winning Super Bowl XII, and a co-MVP of the game with Randy White.