Art Modell, a longtime professional football team owner who engineered many of the NFL’s lucrative television contracts, including “Monday Night Football,” and who angered one city and thrilled another in 1996, when he moved the Cleveland Browns to Baltimore, died Sept. 6 at Johns Hopkins Hospital in Baltimore. He was 87.

The Baltimore Ravens, the team Mr. Modell formerly owned, announced his death. The cause was not disclosed, but he had a history of heart attacks and strokes.

In 1961, Mr. Modell bought controlling interest in the Cleveland Browns for $3.9 million, a record for an NFL franchise at the time. He quickly made his mark as one of the league’s most influential owners.

As a onetime TV producer who made a small fortune by selling television advertising, he led the NFL’s television committee for 31 years. Along with NFL Commissioner Pete Rozelle, Mr. Modell negotiated the TV contracts that made NFL owners immensely rich — and made pro football the nation’s most popular spectator sport.

“Television was my game,” he told the Baltimore Sun in 2010. “And that was the game that made the league famous.”

When Mr. Modell entered the league in 1961, total TV revenues were less than $5 million a year, shared among 14 teams. In 2013, the 32 franchises now in the NFL will take in more than $6 billion in combined TV rights, according to a report by W.R. Hambrecht & Co., a sports marketing firm.

“I’m not much of a visionary,” Mr. Modell told The Washington Post in 2003, “but I could see that this rectangular box and the rectangular field were perfectly matched. Baseball on TV wasn’t so great. Pro football was going to be a big thing.”

Along with Rozelle and TV executive Roone Arledge, Mr. Modell helped launch “Monday Night Football” in 1970, marking the first time sports appeared regularly on prime-time television.

“I believe very strongly that Art Modell is one of the most important figures in the history of the modern NFL,” former NBC-TV president Dick Ebersol said in a statement. “He and Pete Rozelle developed the magic formula that married the potential of television to the game.”

Mr. Modell also played a major role in the 1970 merger of the NFL and the rival American Football League, forming a united and formidable football league. In 2002, Mr. Modell named Ozzie New­some general manager of the Baltimore Ravens — the first African American to hold the job in the NFL.

After taking over the Cleveland franchise in 1961, Mr. Modell sat on corporate boards and was a huge presence in the community. The Browns became a strong team on the field, led by the powerful running of Jim Brown, whom Mr. Modell considered “the greatest football player of all.” Cleveland won the NFL championship in 1964 and for years remained one of the best teams in the league.

The Browns routinely drew more than 70,000 fans a game to rickety Municipal Stadium, and all of them were infuriated when Mr. Modell announced in November 1995 that he was moving the team to Baltimore. He said the city had reneged on promises to build a new stadium and that he was risking bankruptcy by staying in Cleveland.

After Baltimore had lost its previous NFL franchise, the Colts, when owner Robert Irsay moved the team to Indianapolis in 1984, local political leaders assured Mr. Modell that Baltimore would welcome his team. Within two years, a new publicly financed stadium was built for the rechristened Baltimore Ravens. In 2001, the Ravens won the Super Bowl.

Even though Cleveland was awarded a new NFL franchise in 1999 — with the Browns’ old name and colors — the region never forgave Mr. Modell.

“People haven’t just cut the cord and moved on when it comes to Modell,” Ken Roda, a Cleveland sports-radio host, told USA Today in 2001. “ The way he betrayed the fans here, it’s something they will take to the grave with them.”

Arthur Bertram Modell was born June 23, 1925, in Brooklyn, N.Y. He dropped out of high school at 15 to work as an electrician’s helper in a shipyard. He later went to night school and began working in television in the 1940s.

An early marriage ended in divorce. His wife of 42 years, actress Patricia Breslin Modell, died in 2011.

Mr. Modell adopted her sons from a previous marriage, David and John Modell, who survive, along with six grandchildren.

In 2003, Mr. Modell sold all but 1 percent of the Ravens to businessman Steve Bisciotti for a reported $600 million.

In Baltimore, Mr. Modell and his wife donated millions of dollars to educational, medical and cultural groups, but he was forever shadowed by the city he left behind. Many football observers believe the Cleveland fiasco is the reason he has never been elected to the Pro Football Hall of Fame.

But he believed the financial situation in Cleveland left him no alternative but to move to another city without a football team.

“I didn’t give up 35 years of my life,” he said in 1996, “where I was part of everything that went on in Cleveland, because I happen to like crab cakes. I moved for a legitimate reason.”