Carlos Fuentes, the politically engaged Mexican novelist and irrepressible bon vivant who stood at the forefront of Latin American letters for more than half a century, died May 15 at a hospital in Mexico City. He was 83.

Mexico’s National Council for Culture and the Arts announced the death but did not disclose the cause. He was being treated for heart problems.

A diplomat’s son, Mr. Fuentes was working for the Mexican Foreign Ministry when he catapulted to prominence with his first novel, “Where the Air is Clear” (1958). Presenting an extravagant portrait of inequality and moral corruption in modern Mexico, the book established its 29-year-old author as a daring social critic and prose stylist and helped usher in a renaissance in Latin American literature known as the “Boom.”

As his literary career progressed, Mr. Fuentes blended his fascination with politics, and his fervent depiction of erotic couplings, with broader themes such as the inescapable influence of history, the intersection of native and European cultures, and the betrayal of national ideals for personal gain.

He wrote dozens of books, including “The Death of Artemio Cruz” (1962) and “Terra Nostra” (1975), and he earned the highest literary honors in the Spanish-speaking world. In the United States, Mr. Fuentes is best known for “The Old Gringo” (1985), which became the first novel by a Mexican to appear on the New York Times bestseller list. Loosely based on the disappearance of the journalist Ambrose Bierce in Mexico in 1913, “The Old Gringo” was turned into a film starring Jane Fonda and Gregory Peck.

Although Mexico was the overriding subject of his work, Mr. Fuentes spent most his life living in Europe and the United States. Having spent six formative years in Washington as a child, Mr. Fuentes chose to think of himself as a “transopolitan” who felt at home anywhere history and culture were valued or debated.

In addition to his career as a novelist, Mr. Fuentes led an intellectually restless life as a political provocateur, an essayist, a screenwriter and playwright, an editor, an ambassador and a cultural historian.

Physically striking in his youth, with wavy brown hair and a mustache, he added to his luster by romancing movie stars Jean Seberg and Jeanne Moreau. He socialized with many of the world’s leading artists and intellectuals, including the American novelist William Styron, Spanish filmmaker Luis Bunuel and Swiss playwright Friedrich Durrenmatt.

As his star rose, Mr. Fuentes promoted other Latin American novelists, particularly his close friend Gabriel Garcia Marquez, the Colombian writer and future Nobel laureate whose work was largely unknown when they met in the 1960s.

According to Garcia Marquez biographer Gerald Martin, Mr. Fuentes’s international contacts made him the Boom’s most important “creator and propagandist,” a man whose “intellectual generosity was unrivaled.”

Mr. Fuentes was a prolific writer into his 70s and 80s, remaining adamant that words should never simply delight but should challenge or even exasperate.

“I believe in books that do not go to a ready-made public,” Mr. Fuentes told The Washington Post in 1988. “I’m looking for readers I would like to make. To win them, to create readers rather than to give something that readers are expecting. That would bore me to death.”

He was almost as well known for his unstoppable flow of opinion on Mexican and American politics as for his creative writing. In the Cold War era of uprisings, revolutions and political turmoil, Mr. Fuentes became one of Latin America’s most visible left-wing artists of conscience.

In a 1983 Harvard commencement speech, Mr. Fuentes admonished the United States for its “brutal diplomacy” in Nicaragua while President Reagan’s secretary of defense, Caspar Weinberger, was sitting in the front row. The author had been a longtime supporter of the left-wing Sandinista government, which the United States tried to overthrow with help from the rebels known as the contras.

“You must demonstrate your humanity and your intelligence here in this house we share, our hemisphere,” Mr. Fuentes asserted in his Harvard speech, “or nowhere shall you be democratically credible.”

Within Mexico, he was often the target of printed attacks from peers and literary critics angered by the declarations made by an expert on Mexico who lived mostly outside the country. (“The language of Mexicans springs from abysmal extremes of power and impotence, domination and resentment,” he once wrote.)

The most scathing volley was fired by Mexican historian Enrique Krauze in a 1988 article about Mr. Fuentes titled “The Guerrilla Dandy.”

Arguing that Mr. Fuentes was “a foreigner in his own country” who “claimed credentials that he does not have” and used Mexico as a “theme” to further his career abroad, Krauze declared that his writings about the country were simplistic, “frivolous” and “all too often, false.”

The article caused a scandal, in part, because many readers interpreted it as an effort to oust Mr. Fuentes from serious consideration for the Nobel Prize for literature. The article was published in the New Republic and Vuelta, a magazine edited by Krauze’s mentor, the eminent Mexican poet and critic Octavio Paz.

After it was published, Paz and Mr. Fuentes, who had been friends for almost 40 years, never spoke again. Mr. Fuentes later brushed off the affair when speaking to New York Magazine. “I love having critics for breakfast,” he said. “I’ve been having them for 30 years in Mexico — just eating them like chicken, then throwing the bones away.”

Carlos Fuentes Macias was born in Panama City to Mexican parents on Nov. 11, 1928. His father was a career diplomat who was posted to the Mexican Embassy in Washington from 1934 to 1940 and who later served as Mexico’s ambassador to Italy and Portugal.

While in Washington, the younger Fuentes became fluent in English and an enthusiast of American movies and magazines.

It was also a period in which he began to understand himself as Mexican. The catalyzing event occurred on March 18, 1938, when Mexico expropriated its foreign-owned oil holdings. As a result, Mr. Fuentes was ostracized at the District’s H.D. Cooke Elementary School.

“Nobody would talk to me,” he later recalled, “because there were screaming headlines every day talking about Mexican communists stealing ‘our’ oil wells.” In response, he said he became “a terrible Mexican chauvinist” who shouted, “Death to the gringos!” during the screening of a Western at a movie theater.

As Mr. Fuentes moved with his family to Chile, Argentina and, ultimately, Mexico, he grew interested in a literary career, but his parents warned him that he “would die of hunger” if he tried to support himself as a writer.

He enrolled in law school at the National University of Mexico, but he focused his considerable energies less on academics than other pursuits.

“As a student in Mexico City,” he said, “I got up at 6, took a collective taxi to the law school, where I had classes from 8 to 11, went to work at the Foreign Ministry till after 3, came home, had a light lunch, banged the typewriter till 7 or 8 in the evening to get the novel done, and then — I was a young man — would go out with girls, would go to bars and mambo clubs, and come home rather late, thinking that next day I could do it all again.”

By 1957, he had become the head of cultural relations at the Foreign Ministry, had published his first collection of stories (“The Masked Days,” 1954) and had co-founded the influential literary journal Revista Mexicana de Literatura.

The publication of “Where the Air is Clear” transformed Mr. Fuentes into a national celebrity, but critics generally hail “The Death of Artemio Cruz” and “Terra Nostra” as Mr. Fuentes’s most accomplished works. Both were told from the perspective of multiple narrators, a hallmark of Mr. Fuentes’s writing that was meant to evoke “the complexities of a human or national personality,” critic Karen Hardy once wrote.

Modeled partly on Orson Welles’s 1941 movie “Citizen Kane,” “The Death of Artemio Cruz” recounts the deathbed reflections of a shrewd newspaper magnate and ex-revolutionary whose wealth and political power grow in direct proportion to his moral decay.

It is considered by many critics to be the best novel written about Mexico’s 1910 Revolution and was among the first Latin American novels to employ a stream-of-consciousness narrative.

Writing in the New York Times, literary critic Mildred Adams praised “the scope of the human drama it pictures, the corrosive satire and sharp dialogue, the occasional reach for the stars.”

“Terra Nostra,” often regarded as Mr. Fuentes’s most ambitious novel, is a massive, surreal work that traces the decline of the Spanish empire to King Philip II’s animosity toward Jews and Arabs.

Writing in Newsweek, author and critic Peter S. Prescott called “Terra Nostra” both a “masterpiece” and “unreadable.” The novel won Latin America’s most prestigious literary prize, the Romulo Gallegos award.

In 1959, Mr. Fuentes quit his post at the Foreign Ministry and traveled to Havana, where Fidel Castro had just established Latin America’s first socialist state.

Like many Latin Americans, Mr. Fuentes initially saw the Cuban revolution as a victory for self-determination, and he championed Castro’s cause in articles and interviews, as well as in the newspaper he had helped start in Mexico, El Espectador.

He soured on Castro when Cuban officials labeled Mr. Fuentes a traitor in 1965 for attending an international writers conference in New York. Decades later, he told Mother Jones magazine, “Cuba needs a dose of perestroika.”

In the 1960s, Mr. Fuentes secured his reputation as a provocateur when his book “A Change of Skin” (1967), the story of four people and their Holy Week pilgrimage from Mexico City to Veracruz, was banned by the government of Gen. Francisco Franco in Spain. Before the ban — on the grounds that it was “pornographic, communistic, anti-Christian, anti-German and pro-Jewish” — the book had received a major literary prize in Barcelona.

His literary glamour and his preference for Savile Row suits kept him a fixture on an international social circuit of prominent artists. His first marriage, to Mexican movie star Rita Macedo, lasted more than a decade and endured affairs with Moreau and Seberg, the latter of whom he met when she was filming a Western in Mexico.

He later memorialized their tryst in his 1994 novel “Diana: The Goddess Who Hunts Alone.”

In the 1970s, Mr. Fuentes served two years as Mexico’s ambassador to France. He also married journalist Silvia Lemus, whom he met when she interviewed him for Mexican television. Mr. Fuentes and Lemus outlived their two children.

Their son, Carlos, died of complications related to hemophilia at 25. Their daughter, Natasha, died in 2005 at 30. There were conflicting accounts of her death, which was attributed to suicide, drug overdose and murder, and Mr. Fuentes never elaborated publicly. “Tragedy,” he called Natasha’s death when pressed for details.

Besides his wife, survivors include a daughter from his first marriage, Cecilia Fuentes Macedo.

Throughout the 1980s, Mr. Fuentes continued to collect literary laurels. He received Mexico’s National Prize in Literature, became Harvard’s first Robert Kennedy professor of Latin American Studies and garnered the Miguel de Cervantes Prize, bestowed by King Juan Carlos of Spain.

In 1992, Mr. Fuentes reasserted his status as Latin America’s leading cultural historian when the Discovery Channel aired his five-part television series, “The Buried Mirror.” Tracing the history of Hispanic culture from its origin in Spain to its development in Madrid, Buenos Aires, Mexico City and Los Angeles, the series was accompanied by a nonfiction book of the same title.

“When I sit and write, I am master of the world,” Mr. Fuentes told the New York Times, in discussing the TV series. “For one brief moment, I am God. I create reality. In literature, imagination and language are reality. The possibility of being as free with the camera as we are with the pen is a fantastic prospect for the creative life of the 21st century.”

Valdes is a freelance writer.