Nobel Prize-winning author Günter Grass, best known for his book "The Tin Drum," has died at age 87 at a hospital in Luebeck, Germany. Grass’s publisher, Steidl, made the announcement, but has released no details of the cause of death. (Reuters)

Günter Grass, the Nobel Prize-winning author of “The Tin Drum” and other novels that made him known around the world as the moral conscience of 20th-century Germany, a reputation that faltered when he belatedly revealed that he had served as a young soldier in Hitler’s SS, died on April 13 at a hospital in Luebeck, Germany. He was 87.

His publisher, Steidl, announced the death but did not disclose the cause..

With his novels, plays, articles and speeches, Mr. Grass became one of Germany’s foremost intellectuals and gadflies. The themes that consumed his literature — guilt, atonement and hypocrisy — were also central to his political commentary. He could be shrill and polarizing, a self-professed “troublemaker” who cultivated what he described as a “tendency to bring out into the open what had too long been swept under the carpet.”

His picaresque novel “The Tin Drum,” in which he created a diabolical dwarf to symbolize his country’s stunted morality during and after Nazism, brought him near-universal literary acclaim after its publication in 1959. When Mr. Grass received the Nobel Prize for Literature in 1999, the Swedish Academy credited the book with having granted German literature “a new beginning after decades of linguistic and moral destruction.”

For decades, Mr. Grass pursued a career, parallel to his literary work, as a political activist and liberal provocateur. He advocated for environmental conservation, debt relief for poor countries and generous policies regarding political asylum. The United States, and what he regarded as its militarism, was a frequent target.

“How impoverished must a country be before it is not a threat to the U.S. government?” he wrote after visiting strife-torn Nicaragua in 1982 as a supporter of the left-wing Sandinista movement.

He reserved his most biting commentary for fellow Germans, unremittingly spotlighting the role of ordinary people in the rise of the Nazi regime. In 1985, he condemned as “a defilement of history” a visit by President Ronald Reagan and West German Chancellor Helmut Kohl to a military cemetery in Bitburg, Germany, where some SS soldiers had been buried.

During his country’s reunification several years later, Mr. Grass spoke out against the “annexation” by prosperous West Germany of poorer East Germany, comparing it to Nazi expansionism.

After such statements, when Mr. Grass revealed that he served briefly in the Waffen SS, the combat arm of the infamous security force led by Heinrich Himmler, his admission sparked international outrage.

The full facts of his military record began to emerge in 2006 with the publication of his memoir “Peeling the Onion.” In one interview with a German newspaper, he said of his past reticence, “It weighed on me. My silence during all these years is one reason that led me to write this book. It had to come out.”

For decades, Mr. Grass had openly discussed his time in a Hitler youth group, his brainwashing by Nazi propaganda, his unsuccessful attempt to join the submarine corps at 15 and his conscription into the army at 17.

What he had not revealed was that, in the waning days of the war, he served as a tank gunner in the 10th SS Panzer Division. He claimed that he never fired a shot and that he was unaware of the organization’s record of atrocities in concentration camps and elsewhere.

“I did not then know as a 17-year-old that it was a criminal unit,” he told the London Guardian in 2010. “I thought it was an elite unit.”

Political conservatives in Germany called on him to return his literary honors. And many German intellectuals, including his erstwhile allies on the left, distanced themselves from Mr. Grass. This was especially the case following his publication in 2010 of a poem, “What Must Be Said,” warning that Germany might be complicit in war crimes because it sold military equipment to Israel, and his criticism in 2013 of Chancellor Angela Merkel for having been in the East’s Free German Youth movement, the communist regime’s equivalent of the Hitler Youth.

The influential German weekly Der Spiegel said that Mr. Grass had “jumped the shark. His words have lost much of their weight.”

His defenders, including authors Salman Rushdie and John Irving, argued that his body of work was not diminished by the few wartime months he spent as a teenager on the wrong side of history.

“If Grass had not been living with this wretched little skeleton in his closet, he might never have written a word,” journalist Nathan Thornburgh wrote in Time magazine in 2006. “Instead, a haunted Grass cranked out a series of brutal novels about the war [that] helped his entire country stave off collective amnesia for decades.”

Reaction to ‘Tin Drum’

While in the SS, Mr. Grass was captured by the Americans and forced to visit the newly liberated Dachau concentration camp. After his release from a POW camp in 1946, he worked in a potash mine and as a stonemason’s apprentice, studied painting and sculpture in Düsseldorf, and played washboard in a jazz group.

In West Berlin, he joined a group of similarly restless, avant-garde intellectuals who called themselves Group 47. He wrote poetry and plays before moving to Paris to complete “The Tin Drum.” The main character was born, Mr. Grass said, when he attended a dinner party where he saw a child crawl underneath a table, oblivious to the adult world around him, to play a toy drum.

The novel centers on Oskar Matzerath, who stops growing at age 3 out of revulsion for the duplicity of the adult world. Nevertheless, he leads a life of petty crime and deception amid the Nazi horrors. Among his extraordinary abilities is his power to break glass with his high-pitched voice, an allusion to Kristallnacht — the “night of broken glass” in 1938 — when Nazi thugs destroyed Jewish-owned homes and businesses.

Oskar narrates his story retrospectively from a mental institution, beating on a toy drum to a rhythm that transports him to the past.

At the time of its initial printing, “The Tin Drum” was hailed as a rediscovery of modernism at a time when German fiction was still recovering from Nazi doctrine and when many of the country’s writers had ignored the recent past.

“In Germany, there was a real sense that the Nazis were high-up people and that average Germans were the victim of these events as much as anybody else,” said Rebecca Braun, a professor of German studies at Lancaster University in England and the author of a book about Mr. Grass. “ ‘The Tin Drum’ was the first major work implying that regular Germans got into bed with the Nazis.”

Mr. Grass was among the first prominent West Germans to reject his government’s assurances that Germans displaced from territories that became part of Poland, Czechoslovakia and the Soviet Union after World War II would someday return to their ancestral homes. He said he wrote “The Tin Drum” in part to push back against the notion that those lost provinces might someday be recaptured.

Published in the United States in 1963, the book was translated into 20 languages, and a 1979 film version won the Academy Award for best foreign-language movie. In the New York Times, critic Orville Prescott declared Mr. Grass in 1963 “the most authentic literary talent to appear in Germany in 25 years” and said he had produced “a fantasy, a farce, a ferocious satire and a comic extravaganza.”

Mr. Grass followed “The Tin Drum” with “Cat and Mouse” (1961), about a German soldier who wins the Iron Cross but is forced into the role of social outcast in part because of his comically protruding Adam’s apple. “Dog Years” (1963) is a “Ulysses”-like epic about a Jew who makes scarecrows and dresses them in Nazi uniforms, and the boyhood friend who eventually betrays him.

Mr. Grass, who joined Germany’s Social Democratic Party, could be imaginative and forceful when writing about current events and politics. “From the Diary of a Snail” (1972) presents a fictionalized account of the author’s role as a speechwriter for West German Chancellor Willy Brandt.

The Flounder” (1977), a comic novel, was based on a Brothers Grimm cautionary tale about a talking fish with magical powers. In Mr. Grass’s hands, it became a controversial take on women’s rights and man’s chaotic role in history. “The Rat” (1986) was a surreal prophecy of nuclear extermination told by a rat and in which rodents inherit the Earth.

One of his most celebrated later novels, “Crabwalk” (2002), was a multi-generational story that illuminated the ascent of neo-Nazism. The book also looked back on the suffering by workaday Germans during World War II, including the Soviet sinking of a ship packed with thousands of German refugees in 1945.

The book ruminated on one of Mr. Grass’s most enduring motifs: the danger and futility of trying to suppress history.

“History, or, to be more precise, the history we Germans have repeatedly mucked up, is a clogged toilet,” the narrator of “Crabwalk” says. “We flush and flush, but the [expletive] keeps rising.”

Illustrated his own books

Günter Wilhelm Grass was born Oct. 16, 1927, in the semiautonomous region then known as the Free City of Danzig, which came under Nazi control in 1939. It is now the Baltic Sea port of Gdansk, Poland.

His father was a grocer and a minor government official who supported Hitler and pushed his son to be an engineer. His mother, an opera lover who kept volumes of Tolstoy and Dostoevsky in their two-room house, encouraged her son’s artistic side.

Mr. Grass began writing at 13, shortly after the war broke out, and submitted his first story to a Hitler Youth magazine. The execution of a relative who tried to defend the Danzig post office from the Nazis was incorporated into “The Tin Drum,” as was the rape of Mr. Grass’s mother by Soviet soldiers, an event that he found out about only after her death.

“My mother never spoke about it, though I tried to get her to speak,” he told the Guardian. “There are things for which one can’t find words.”

His first marriage, to ballet dancer Anna Schwarz, ended in divorce. In 1979, he wed organist Ute Grunert. Besides his wife, survivors include four children from his first marriage; two daughters from other relationships; two stepsons; and many grandchildren.

Mr. Grass illustrated many of his own books and dust jackets. Immediately recognizable for his walrus mustache and heavily-lidded eyes, Mr. Grass maintained his celebrity and continued to provoke outrage well into his 80s. In 2012, he was declared persona non grata by the Israeli government for his poem “What Must Be Said,” which cast the country as a threat to world peace for its bellicose posture toward Iran.

At times, his stridency suggested that he had steeled himself to controversy. But there were signs, especially after his SS confession, of his vulnerability.

“I always face the question: Should I grow myself a thick skin and ignore it, or should I let myself be wounded?” he told the Guardian in 2010. “I’ve decided to be wounded, since, if I grew a thick skin, there are other things I wouldn’t feel any more.”

Otis is a freelance writer. Staff writer Marc Fisher contributed to this report.