George Steinbrenner, who bought a declining Yankees team in 1973, promised to stay out of its daily affairs and then, in an often tumultuous reign, placed his formidable stamp on 7 World Series championship teams, 11 pennant winners and a sporting world powerhouse valued at perhaps $1.6 billion, died Tuesday morning at a hospital in Tampa, Fla., where he lived. He was 80.

Enlarge This Image Robert Caplin for The New York Times

George Steinbrenner at opening day 2007. More Photos »

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The cause was a heart attack, the Yankees said. Mr. Steinbrenner had been in failing health for several years.

His death came eight months after the Yankees won their first World Series title since 2000, clinching their six-game victory over thePhiladelphia Phillies at his new Yankee Stadium, and two days after the team’s longtime public-address announcer,Bob Sheppard, died at 99.

A pioneer of modern sports ownership, Mr. Steinbrenner started the wave of high spending for players when free agency arrived, and he continued to spend freely through the Yankees’ revival in the late ’70s and early ’80s, the long stretch without a pennant and then renewed triumphs under Joe Torre as manager and General Manager Brian Cashman.

The Yankees’ approximately $210 million payroll in 2009 dwarfed all others in baseball, and the team paid out millions in luxury tax and revenue-sharing with small-market teams.

In the frenetic ’70s and ’80s, when general managers, field managers and pitching coaches were sent spinning through Mr. Steinbrenner’s revolving personnel door (Billy Martin had five stints as the manager), the franchise became known as the Bronx Zoo. In December 2002, Mr. Steinbrenner’s enterprise had grown so rich that the president of the Boston Red Sox, Larry Lucchino, frustrated over losing the pitcher Jose Contreras to the Yankees, called them the “evil empire.”

But Mr. Steinbrenner — who came to be known as the Boss — and the Yankees thrived through all the arguments, all the turmoil, all the bombast. Having been without a pennant since 1964 when Mr. Steinbrenner bought them, enduring sagging attendance while the upstart Mets thrived, the Yankees once again became America’s marquee sporting franchise.

Despite his poor health, Mr. Steinbrenner attended the opening game at the new Yankee Stadium in April 2009, sitting in his suite with his wife, Joan (pronounced Jo-ann). When he was introduced and received an ovation, his shoulders shook and he cried.

He next appeared at the Yankees’ new home for the first two games of the World Series, then made his final appearance at the 2010 home opener, when Joe Girardi, the manager, and Derek Jeter, the team captain, came to his suite to present him with his 2009 World Series championship ring.

After the World Series victory, Girardi said, “To be able to deliver this to the Boss, to the stadium he created and the atmosphere he created around here, it’s very gratifying to all of us.” Mr. Steinbrenner, the Yankees’ principal owner and chairman, had ceded increasing authority to his sons, Hal and Hank, who became co-chairmen in May 2008. Hal Steinbrenner was given control of the team in November 2008 in a unanimous vote by the major league club owners.

Mr. Steinbrenner lived year-round in Tampa, but he became a New York celebrity and a figure in popular culture. He was lampooned, with his permission, by a caricature in the sitcom “Seinfeld,” portrayed by the actor Lee Bear, who was always photographed from behind at the Boss’s desk while Larry David, the show’s co-creator, provided the voice. George Costanza (Jason Alexander) became the assistant to the team’s traveling secretary, whose duties included fetching calzones for Mr. Steinbrenner.

Mr. Steinbrenner also appeared in a Visa commercial with Jeter, calling him into his office to admonish him. “You’re our starting shortstop,” Mr. Steinbrenner said. “How can you possibly afford to spend two nights dancing, two nights eating out and three nights just carousing with your friends?” Jeter responded by holding up a Visa card. Mr. Steinbrenner exclaimed “Oh!” and the scene shifted to Mr. Steinbrenner in a dance line with Jeter at a night spot.

Rebuilding a Franchise

Mr. Steinbrenner was the central figure in a syndicate that bought the Yankees from CBS for $10 million. When he arrived in New York on Jan. 3, 1973, he said he would not “be active in the day-to-day operations of the club at all.” Having made his money as head of the American Shipbuilding Company, based in Cleveland, he declared, “I’ll stick to building ships.”

But four months later, Michael Burke, who had been running the Yankees for CBS and had stayed on to help manage the franchise, departed after clashing with Mr. Steinbrenner. John McMullen, a minority owner in the syndicate, soon remarked that “nothing is as limited as being a limited partner of George’s.”

Mr. Steinbrenner emerged as one of the most powerful, influential and, in the eyes of many, notorious executives in sports. He was the senior club owner in baseball at his death.

Yankee Stadium underwent a major renovation in the mid-1970s, but that did not satisfy Mr. Steinbrenner. He cast an eye toward New Jersey, pressed for a new stadium in Manhattan and ultimately got a $1.5 billion stadium built in the Bronx, alongside the original House That Ruth Built.

He found new revenue streams from cable television, first in a longtime deal with the Madison Square Garden network and then with the creation of the Yankees’ YES network. The franchise also engineered lucrative marketing deals, notably a 10-year, $95 million apparel agreement with Adidas.

Mr. Steinbrenner usually adored his players but at times insulted them. He called outfielder Paul O’Neill “the ultimate warrior.” (Steinbrenner idolized Generals MacArthur and Patton.) But he derided the star outfielder Dave Winfield, calling him Mr. May, pointedly contrasting him with Reggie Jackson, who had been known as Mr. October for his clutch hitting in the postseason.

Mr. Steinbrenner was twice barred from baseball, once after pleading guilty to making illegal political campaign contributions. By October 1995, when he was fined for complaining about the umpires in a playoff series with the Seattle Mariners, Mr. Steinbrenner had accumulated disciplinary costs of $645,000.

When he was not phoning his general managers and managers with complaints or advice, he meddled in the smallest matters of ballpark maintenance. He was often portrayed by the news media as a blowhard and a baseball know-nothing.

“George is a great guy, unless you have to work for him,” Lou Piniella, who managed the Yankees twice in the 1980s, told Sports Illustrated in 2004. Mr. Steinbrenner saw himself as sticking up for the everyday New Yorker, though the price of Yankees tickets kept rising.

“I care about New York dearly,” he told Sports Illustrated in 2004. “I like every cab driver, every guy that stops the car and honks, every truck driver. I feed on that.”

Drawing on Early Influences

He helped many charities and individuals in need and as a board member was a major fund-raiser for the historically black Grambling State University in Louisiana.

George Michael Steinbrenner III was born on July 4, 1930, the oldest of three children, and reared in the Cleveland suburb of Bay Village. His father, Henry Steinbrenner, graduated from the Massachusetts Institute of Technology with a degree in naval architecture and engineering and starred as a collegiate hurdler before taking over the family’s maritime shipping business.

Young George tried to please his father by taking up hurdling and running a home-based business that raised chickens and sold their eggs.

“He was a tough taskmaster,” Mr. Steinbrenner once said of his father. “You know, if I ran four races in track, won three and lost one, he’d say, ‘Now go sit down and study that one race and see why you lost it.’ ”

His mother, Rita, offered a contrasting presence. “It was my mom who gave me compassion for the underdog and for people in need,” Mr. Steinbrenner was quoted by Bill Madden in “Steinbrenner: The Last Lion of Baseball” in an apparent reference to his many charitable endeavors.

Mr. Steinbrenner attended Culver Military Academy in Indiana in the mid-1940s. His father, who idolized the Yankees’ Joe DiMaggio and Bill Dickey, took him to Cleveland to watch Indians games, especially when the Yankees came to town. “We were in awe of the Yankees,” Mr. Steinbrenner said.

Mr. Steinbrenner graduated from Williams College in Massachusetts with a degree in English. He served as an Air Force officer, coached high school football and basketball in Ohio, and was briefly an assistant football coach at Northwestern and Purdue.

He returned to Cleveland in 1957 to join the family’s shipping firm, Kinsman Marine Transit, which carried Great Lakes cargo. He also operated the Cleveland Pipers basketball team.

In 1967, Mr. Steinbrenner began obtaining stock in the American Shipbuilding Company, based in Lorain, Ohio. He eventually took it over, merging it with Kinsman. By the time he gained control of the Yankees six years later, the company had greatly strengthened its operations.

Gabe Paul, a veteran baseball executive who helped arrange Mr. Steinbrenner’s purchase of the Yankees, and Lee MacPhail, the holdover general manager from the CBS years, were expected to make the personnel decisions when Mr. Steinbrenner arrived.

But he quickly became immersed in baseball decisions, spending large sums to end the long pennant drought, starting with the acquisition of the star pitcher Catfish Hunter. Meanwhile, he ran into trouble in a matter far beyond the ball fields.

In November 1974, Commissioner Bowie Kuhn suspended him for two years — a term later reduced to 15 months — after he pleaded guilty to two charges, one a felony and the other a misdemeanor: conspiring to make illegal corporate contributions to President Richard M. Nixon’s 1972 re-election campaign, and trying to “influence and intimidate employees” of his shipbuilding company to lie to a grand jury about the matter. He was fined $15,000 in the criminal case but given no jail time.

“Everybody has dents in his armor,” Mr. Steinbrenner told The New York Times in 1987. “That’s something I have to live with.” President Ronald Reagan pardoned him in January 1989, during his final days in office.

Personnel Hired to Be Fired

When free agency arrived as a result of an arbitrator’s decision in 1975 that nullified the reserve clause, which had bound players to their teams, Mr. Steinbrenner stepped up his spending.

The Yankees signed the slugger Reggie Jackson and the ace relief pitcher Goose Gossage, and they won the World Series in 1977 and 1978.

Mr. Steinbrenner changed managers and general managers with abandon, punctuated by the bizarre comings and goings of Martin. The oddest sequence began on July 24, 1978, when Martin resigned as manager, presumably a step ahead of being fired, after saying of Jackson and Mr. Steinbrenner: “The two of them deserve each other. One’s a born liar; the other’s convicted,” a reference to Mr. Steinbrenner’s guilty plea in the illegal-contributions case.

Only five days later, on Old-Timers’ Day at Yankee Stadium, Martin was introduced as the Yankees’ manager for 1980. Instead, he returned in June 1979, replacing the fired Bob Lemon, only to be fired himself a month after that season ended.

Another furor arose in 1985, this one surrounding Yogi Berra, the Yankees’ Hall of Fame catcher, who had become the manager. After declaring that “Yogi will be the manager the entire season, win or lose,” Mr. Steinbrenner fired him with the team off to a 6-10 start. Berra, furious, refused to set foot inside Yankee Stadium until Mr. Steinbrenner apologized 14 years later. By 1990, he had switched managers 18 times and hired 13 general managers.

Then came more trouble. In July 1990, Commissioner Fay Vincent ordered Mr. Steinbrenner to step aside as the Yankees’ managing partner for making a $40,000 payment to a confessed gambler named Howard Spira in return for Mr. Spira’s seeking damaging information about Winfield. Mr. Steinbrenner had been displeased with Winfield’s performance on the field, and the two had feuded over contributions Mr. Steinbrenner was to make to Winfield’s philanthropic foundation.

Mr. Steinbrenner resumed control of the Yankees in 1993, and three years later, they were World Series champions, beginning a long run of dominance.

By the 1990s, with free agents becoming ever more expensive, Mr. Steinbrenner acknowledged the need to develop the Yankees’ minor league system. The Yankees swept to championships with homegrown talent like Jeter, center fielder Bernie Williams, catcher Jorge Posada and pitchers Andy Pettitte and Mariano Rivera. But they also assumed more than $100 million in payments owed to Alex Rodriguez, who arrived in a trade with the Texas Rangers, and obtained the high-priced Jason Giambi, Roger Clemensand Randy Johnson.

In 2002, an investment group that included the Yankees formed the YES network to carry many games and broadcast Yankees-related programming. YES had $257 million in revenue in 2005, for the first time surpassing MSG as the country’s top regional sports network, according to Kagan Research.

The Yankees’ management achieved stability in the last decade as the team captured World Series championships in 1996 and every year from 1998 to 2000. But the Yankees faltered after that in their bid for another World Series title, and when they were knocked out of the playoffs by the upstart Detroit Tigers in 2006, speculation arose that Mr. Steinbrenner would fire Torre.

Torre, the manager since 1996, and Mr. Cashman, the general manager since 1998 and a frequent object of Mr. Steinbrenner’s criticism, stayed on.

But in October 2007 in a newspaper interview, Mr. Steinbrenner threatened to fire Torre if the team did not advance beyond the first round of the playoffs. The Yankees were eliminated by the Cleveland Indians in that round, and soon afterward, Torre departed after rejecting a one-year contract extension with a cut in his guaranteed salary.

Running Things His Way

Even in his earliest days running the Yankees, Mr. Steinbrenner acknowledged that he seemed to rule through fear. “Some guys can lead through real, genuine respect,” he told Cleveland magazine in 1974, “ but I’m not that kind of a leader.”

Always fastidious about his own grooming, he insisted that his players shun unruly hair and beards, displaying something of the disciplinarian he had been at home, with his children. He admitted he had been overbearing and even verbally abusive toward them. His daughter Jennifer said in 2004 that her brothers had absorbed the brunt. “Let’s put it this way: he had very high expectations of us,” she said.

In addition to his wife, Joan, his sons Hal and Hank, and his daughter Jennifer Steinbrenner Swindal, Mr. Steinbrenner is survived by his daughter Jessica Steinbrenner; two sisters, Susan Norpell and Judy Kamm, and several grandchildren.

In his later years, Mr. Steinbrenner spent most of his time in Tampa. He had divested himself of most of his business interests. American Shipbuilding filed for bankruptcy in 1993, but he owned a stud farm in Ocala, Fla., and had entered six horses in the Kentucky Derby over the years. In April 2010, Forbes magazine estimated the Yankees’ value at $1.6 billion. The Red Sox had the second-highest value among major league teams, according to Forbes, far behind the Yankees at $870 million, with the Mets third at $858 million.

In his last years, Mr. Steinbrenner seemed to mellow some. He cried in public on several occasions, including the time he walked past a group of West Point cadets who cheered for him at the Yankees’ 2004 home opener. He cried again in a television interview that day.

“This is a very important thing that we hold the string to,” he said of the Yankees, his voice cracking. “This is the people’s team.”

In building it into a fabulously successful and exceedingly lucrative enterprise, he never lost sight of his credo. As he told The New York Times in 1998: “I hate to lose. Hate, hate, hate to lose.”

George M Steinbrenner