British fans of American football during its boom years in the 1980s needed look no further than Dallas Cowboys coach Tom Landry to understand how different it is from soccer. Landry, stone-faced in his trademark felt hat, was Eisenhower at D-Day, overseeing a well-organised corporation; it was a universe far removed from Brian Clough, Big Ron, Big Mal or Big Anyone.

Landry, who has died of leukemia aged 75, was a study in American irony. A tactical innovator, he was perceived as a gridiron conservative. Deeply religious, he was an incongruous part of the marketing of Dallas as "America's Team", including cheerleaders in American flag hotpants. Intensely loyal, he was fired in the infamous "Saturday Night Massacre".

Landry was always seen in contrast to the more fiery Vince Lombardi. They coached together under Jim Lee Howell with the 1950s New York Giants, Lombardi running the offence and Landry the defence. Lombardi believed in simplicity, inspiring through intensity and fear; Landry was a master strategist, said to enjoy preparing for the game more than the game itself.

Only 29, one year removed from playing, he stopped the mighty Cleveland Browns by devising the 4-3 defence, still standard for most National Football League teams. Lombardi moved to Green Bay, turning the Packers into champions. Two years later, Landry took over the brand-new Cowboys, stocked through an expansion draft with other teams' castoffs. He coped by developing, with general manager Tex Schramm and scout Gil Brandt, computerised scouting, uncovering unlikely gridiron stars like Olympic sprinter Bob Hayes. He won no games in his first season, but within seven years Dallas met Green Bay for the NFL championship, the famed "Ice Bowl", played in temperatures so cold announcer Frank Gifford told his audience he was taking "another bite of coffee". The Packers could dominate most 4-3 defences, so Landry invented the "flex", and developed a shifting, multiple offence that is also standard today.

When the Packers won that game, America saw it as a triumph of Lombardi's individualism over Landry's systems. But consistent success turned Dallas into "America's Team": 20 consecutive winning seasons, 13 division titles, and two Super Bowl victories.

The devout Landry was equally successful with clean-cut stars like Bob Lilly or Roger Staubach and high-livers like "Dandy" Don Meredith or Thomas "Hollywood" Henderson. When Dallas's dark side was revealed in ex-Cowboy Pete Gent's novel North Dallas Forty, later filmed with Nick Nolte, much of America enjoyed the portrayal of the team as America's hypocrites.

When Jerry Jones bought the Cowboys in 1989 and fired Landry the same day, it shocked Texas. Landry was a state high school star who left the University of Texas to join the Air Force when his brother was killed in the war, and flew 30 combat missions in Europe. He returned to Texas before turning pro in New York, and had coached the Cowboys for 29 years. It was the one setback he couldn't overcome. When he left he told his players: "I'll be with you in spirit always". But he cut himself off from Jones's Cowboys, and the days of "America's Team" disappeared forever.

Landry is survived by his wife Alicia, son Tom Jr and daughter Kitty.