Josep Lluís Núñez, president of FC Barcelona, celebrates one of his team’s goals. He was the club’s longest-tenured president, serving from 1978 to 2000. (Sigfrid Casals/Cover/Getty Images)

Josep Lluís Núñez, a Spanish construction magnate who helped grow FC Barcelona into one of the world’s most valuable sports teams, presiding over the acquisition of some of soccer’s finest players and the creation of an influential youth academy while battling with opponents who questioned his approach to the game, died Dec. 3 at 87.

His death was announced in a statement by FC Barcelona, which did not say where or how he died. Mr. Núñez was the organization’s longest-serving president, holding the office from 1978 to 2000. He was investigated for corruption soon after leaving the team, and in 2011 was sentenced to six years in prison — later reduced to 26 months — for attempting to bribe tax inspectors investigating his construction business.

With the motto “more than a club,” Barça, as it is commonly known, has long cultivated its image as an embodiment of democratic ideals and Catalan pride. Similar to the Green Bay Packers of the National Football League, the team is essentially owned by its fans — a group of more than 144,000 “members” who elect the team’s president and, at many home games, chant in favor of Catalan independence at the 17 minute 14 second mark, in a symbolic nod to the year in which King Philip V of Spain captured Barcelona.

Mr. Núñez was known as a businessman, not a sports figure, before Barça’s members elected him president in 1978, following a tumultuous campaign season in which he wooed journalists over lavish seafood dinners, purchased an address list of all the team’s voting members and tarred his opponents with propaganda about their personal lives, according to “La Roja,” a history of Spanish soccer by journalist Jimmy Burns.

He went on to usher in a new, modern era at FC Barcelona, an organization that includes basketball, roller hockey, futsal (a variant of soccer) and handball teams alongside its flagship soccer club.

Mr. Núñez, the team said in a statement, “totally transformed the club. In his first season, 1978-79, the budget was 817 million pesetas, and by 1999-2000 it was a massive 17,594 million,” or roughly $109 million. The growth was fueled by both an expansion of the team’s facilities and increasing success on the pitch.

Mr. Núñez in 2014. (Josep Lago/AFP/Getty Images)

Under Mr. Núñez, the team featured world-class players such as Ronaldo, Diego Maradona and Pep Guardiola, and managers including Dutch soccer great Johan Cruyff, who assembled a formidable squad known as the “Dream Team” in the early 1990s. It also won a spate of championships, including its first European Cup (now known as the UEFA Champions League), in 1992; four titles in the now-defunct European Cup Winners’ Cup; seven titles in La Liga, the Spanish soccer league; and six titles in Spain’s Copa del Rey competition.

The club expanded its home stadium, Camp Nou, to a staggering capacity of 120,000; built a second, smaller stadium nearby; and erected a popular FC Barcelona museum housing trophies and memorabilia. And in 1979, at Cruyff’s suggestion, it set up La Masia, a youth academy that has trained players such as Andrés Iniesta, Xavi Hernández and Lionel Messi, Barça’s current captain and physics-defying forward.

In October, FC Barcelona announced that it had surpassed the $1 billion mark in revenue, a first for a sports team. Forbes valued the organization at $4.06 billion earlier this year, ranking it the fourth most-valuable team in the world, behind only the Dallas Cowboys, Manchester United and archrival Real Madrid.

While Mr. Núñez presided over the growth of a financial powerhouse, his reign was marked by strife with players, managers and fans, for whom expectations were nothing less than a Spanish league title each season, and a Champions League crown to boot.

Managers came and went, and Mr. Núñez was often criticized for transferring athletes who, in his eyes, demanded too much money. (Maradona was forced out after two years; Ronaldo lasted just one season.) After an unexpected European Cup loss in 1986, a large faction of his team rebelled and was dismissed, in an event that become known as the Hesperia Mutiny, for the Barcelona hotel in which the players announced their revolt.

Barcelona defender Gerard Piqué, center, and midfielder Sergio Busquets, right, pay tribute to Mr. Núñez at Camp Nou after his death. (Lluis Gene/AFP/Getty Images)

Mr. Núñez, soccer journalist Phil Ball wrote in “Morbo: The Story of Spanish Football,” “survived players’ rebellions, dozens of votes of no-confidence, petulant star players and Cruyff’s periodic attempts to dislodge him from his throne” before finally retiring in 2000, two years before the end of his term as president. At the team’s last game that season, thousands of Barça fans had waved white handkerchiefs his way, demanding his resignation.

“At the farewell press conference he surrounded himself with the 138 trophies won during his 22-year period: 27 from football, 25 from basketball, 50 from handball and 36 from hockey,” Ball wrote. (According to FC Barcelona, his teams won a total of 175 titles.) “He could instead have mounted a large finger on the screen behind his podium, but the journalists present got the message.”

Josep Lluís Núñez was born in Barakaldo, in the Basque Country just outside Bilbao, on Sept. 7, 1931. The son of a customs officer, he went on to build what was widely regarded as the largest construction company in Catalonia, Núñez i Navarro, before being elected president of FC Barcelona.

Survivors include his wife, Maria Lluïsa Navarro; and two sons, Josep Maria Núñez and Josep Lluís Núñez Jr., a fellow FC Barcelona official who was also convicted on bribery charges.

While Mr. Núñez’s decision to retain or transfer players typically seemed to hinge on money, more personal factors were said to play a role as well. In one history of the team, “Barça Inèdit,” by Manuel Tomás and Frederic Porta, Mr. Núñez was reported to have dispatched Dutch midfielder Johan Neeskens, who was sent to the New York Cosmos in 1979, as a result of a bathroom dispute.

Neeskens, the book’s authors reported, had refused to pass Mr. Núñez a roll of toilet paper under the stall.