In his new documentary film “Slava Ukraini,” Bernard-Henri Lévy, France’s most famous public intellectual, dodges Russian sniper fire in Ukraine, nonchalantly wearing a khaki bulletproof vest over a chic bespoke suit.

He climbs onto a Ukrainian naval vessel in Odessa that is sweeping the Black Sea for Russian mines, his mane of graying hair blowing gently in the wind. And he surveys blown-out apartment blocks in Kyiv, descends into trenches with Ukrainian soldiers in Sloviansk and comforts a mother whose young son is so traumatized by war, he has stopped speaking.

It can be easy to dismiss Lévy — and plenty do — as a 74-year-old reckless war tourist, an heir to a timber fortune playing action hero as Russian missiles rain down on Kyiv, Kharkiv and Mariupol. But instead of spending the last 12 months in his art-filled home on Paris’s right bank or enjoying retirement at his 18th-century palace in Marrakesh, Levy has been braving Russian military assaults, vertigo and what he calls his natural tendency for melancholy to make his Ukraine film.

It was, he said, a necessary cri de coeur to support Ukraine in a conflict he views as nothing less than a battle for the future of Europe, global liberalism and Western civilization.

“In Ukraine, I had the feeling for the first time that the world I knew, the world in which I grew up, the world that I want to leave to my children and grandchildren, might collapse,” he said during an interview at the Carlyle Hotel in New York earlier this month, in which he peppered his accented but fluent English with allusions to Clausewitz, Hegel and Viennese literature.

A philosopher, writer, television personality and filmmaker, Lévy is a quintessentially French invention in a country that fetes its public intellectuals like pop stars. He is so ubiquitous in France that he is known simply as B.H.L., his initials akin to a French luxury brand. But he is also a deeply polarizing character, mocked by some critics as a dilettante or sound bite philosopher.

But Lévy appears aloof from the criticism, viewing his work as a higher calling.

“The moral call never goes silent for me,” Lévy said. “I suppose at one point, I will no longer have the force to reply to the call.”

“Slava Ukraini”— “Glory to Ukraine”— premiered in France on Feb. 22 and is expected to be released in the United States in the coming months. It was shot over the past year during more than 10 trips Lévy made to Ukraine. The film (Lévy’s second about the conflict there) has garnered praise for its unflinching portrayal of the horrors of war. “Without a doubt, Lévy has never filmed and conveyed distress and death with such harshness and such relentless rawness,” observed L’Express, the influential French magazine.

Lévy has spent the past five decades pleading with the West to intervene in seemingly intractable conflicts, inserting himself into battlefields in places like Bosnia, Darfur, Rwanda, Kurdistan, Afghanistan and Libya.

This time, however, he said the stakes were far graver. If President Vladimir V. Putin of Russia weren’t stopped, he warned, there would be a new Cold War, with Moscow, Tehran, China, Turkey and Islamic fundamentalists menacing the world and nuclear despots empowered to blackmail the West.

Those in the U.S. Congress and European capitals who complained that arming Ukraine was too expensive, he said, were quite simply “morons.”

And why does he wear designer suits in a war zone? “Dressing is not important but it is one of the little signs of respect” to the people of Ukraine, Lévy explained.

Born in French Algeria in 1948 to a Sephardic Jewish family, Lévy burst onto the national stage in France in the 1970s, a young, longhaired philosopher railing against the perils of Marxism on the French left. He has written dozens of books, covering politics, philosophy, Judaism and American identity. He co-founded an influential antiracism group, and became a media darling who had the ear of French presidents.

Yet he continues to attract opprobrium. He has been castigated for his outspoken support of Roman Polanski and Dominique Strauss-Kahn, both accused of sexually abusing women. He has been ambushed at least eight times by a Belgian pie-thrower who targets pompous personages, and he is the subject of no fewer than four sometimes-scathing biographies. An aphorism is frequently attributed to him: “God is dead but my hair is perfect.”

“I never said it, it is fake,” he said. “I am ready to find it funny.”

Some critics have also questioned his methodological rigor. In his 2010 book, “On War in Philosophy,” Lévy extensively quotes Jean-Baptiste Botul, a 20th-century philosopher and originator of a school of thought known as Botulism. But Botul never existed and is the satirical invention of the writer Frédéric Pagès. Lévy, at the time, was contrite and complimented the hoaxer for his ruse.

Jade Lindgaard, a French journalist and co-author of “The Impostor: BHL in Wonderland,” a critical investigation of Lévy and his work, argued that Lévy’s influence had waned, in part because he was out of touch with contemporary issues, like climate change and the #MeToo movement.

“To me, he has lost his credibility, probably because of all the mistakes he has made in his writings,” she wrote in an email, adding that his personal style undermined him.

But his defenders write off the attacks as little more than jealousy of his wealth, power and success. (He is married to the actress and singer Arielle Dombasle.) He is, they say, a man seeking to make and shape history, not just write it.

“These people who criticize him are armchair intellectuals who never leave their Parisian salons,” said Marc Roussel, the co-director of “Slava Ukraini.”

Lévy said his first formative moment that inspired him to leave behind the empty rallying cries of the classroom came in his early 20s, when he heeded the call by André Malraux, the French novelist, to help Bangladeshi separatists battling Pakistan. In 1971, he traveled to Bangladesh, his first foray as a war correspondent.

“At that moment, I decided to try and make something happen, to dirty my hands in real history,” he said.

In 1977, Lévy wrote “Barbarism With a Human Face,” in which he rejected Marxism and Maoism. Instead, he said he came to embrace as his guiding philosophy the notion of “tikkun olam,” the idea that Jews have a responsibility to “repair the world” through good deeds.

Lévy said his lodestar was his father, André Lévy, a self-made man who had fled poverty in Algeria as a teenager in the 1930s, and volunteered to fight with the Republicans in Spain against Franco before joining the Free France army and fighting against the Nazis.

When facing the prospect of Bosnian-Serb snipers in Sarajevo, ISIS fighters in the caves of Kurdistan, or Russian mortar fire in Ukraine, Lévy said he often thought of his father’s moral bravery and physical grit.

“To give me courage, I think of my dad climbing Monte Cassino with a group of Moroccan fighters and taking the peak,” he said, referring to a bloody battle in Italy in 1944 which preceded the Allies breaking through German defenses.

Lévy said his belief in the power of individuals to wake up the world was cemented during the war in Bosnia in the 1990s when he went to Sarajevo. He had initially wanted to organize an international brigade to help Muslim Bosniak forces fighting the Serbs, but decided he would be more effective making a film. His father, who pleaded with him not to go to Bosnia, ultimately financed the production, which helped shed light on Serb atrocities against Muslims.

“Bosnia showed me that ideas matter, words can make a difference, decision makers can be convinced and that individuals can be a grain of sand that blocks the machinery,” Lévy said.

In 2011, in a period of roughly two weeks, Lévy played a decisive role in cajoling President Nicolas Sarkozy to intervene in Libya, helping to clear the way for France, the United States and NATO to back a fledgling opposition group and wage a war that helped overthrow the Libyan leader, Col. Muammar el-Qaddafi.

Lévy said intervening in Libya was the “right thing to do.” But some critics of that move point out that Libya has since regressed into mayhem.

While Lévy is closely associated with France, he said his two towering role models were Ernest Hemingway, the physically imposing action man who covered the Spanish Civil War, and F. Scott Fitzgerald, king of the gin-fueled Jazz Age of Paris in the 1920s.

“I like to think with my feet, my hands, my lungs, my flesh,” he said.