Former U.S. senator Mike Gravel, an Alaska Democrat with a flair for the theatrical who rose from obscurity to brief renown by reading passages of the Pentagon Papers into the Congressional Record in an effort to end the Vietnam War and who ran quixotic campaigns for the presidency in 2008 and 2019, died June 26 at his home in Seaside, Calif. He was 91.

The cause was multiple myeloma, said his daughter, Lynne Mosier.

Born into a working-class Massachusetts family of French Canadian immigrants, Mr. Gravel (pronounced gruh-VELL) was drawn to politics at a young age but sensed that he would be hindered by his lack of connections and polish. After graduating from college, he set out for Alaska in 1956 — three years before it became a state — hoping to find greater political opportunities in a place with no entrenched establishment.

Within a few years, Mr. Gravel was prospering in real estate development and won election to the state House of Representatives, rising to the position of speaker in 1965. Buoyed by his telegenic looks, and what he presented as his support for the Vietnam War in a relatively hawkish state, he narrowly unseated an incumbent octogenarian U.S. senator in 1968.

“I said what I said” about Vietnam, he told NPR decades later, “to advance my career.”

In Washington, he reversed his stance and became known among the chamber’s more traditional denizens as a gadfly. He was by his own admission “too abrasive” for backroom persuasion and enjoyed filibustering. His legislative preoccupations, besides ending U.S. involvement in Vietnam, included opposing the Nixon administration’s war on drugs and abolishing the draft.

Mr. Gravel was a freshman senator in June 1971 when he decided to read the Pentagon Papers — a 7,000-page secret government history of the war in Vietnam — into the record.

The New York Times had already printed a part of the papers before Attorney General John N. Mitchell called on the newspaper to stop. The Times initially refused but soon agreed to obey a temporary restraining order by a federal court. The Washington Post then published an excerpt before receiving its own restraining order. Both papers subsequently found themselves before the U.S. Supreme Court.

They had obtained the documents from Daniel Ellsberg, a former Rand Corp. military analyst who had worked on the study and become convinced that White House and Pentagon officials were misleading the public about the disastrous reality on the ground in Vietnam.

Ellsberg also tried to leak the papers to liberal members of Congress. He found little interest among them until he reached Mr. Gravel, who at the time was mounting a filibuster to block the government from renewing the draft.

As he recounted in his 2008 memoir, “A Political Odyssey: The Rise of American Militarism and One Man’s Fight to Stop It,” Mr. Gravel realized that reading aloud the Pentagon Papers would fill time in his filibuster as well as reveal ugly details of the war.

On June 29, 1971, Mr. Gravel convened an obscure subcommittee he chaired dealing with buildings and grounds. He began reading summaries of the papers that chronicled the war, starting with colonial French authorities battling Ho Chi Minh’s communist insurgents.

After about three hours of nonstop reading, shortly after 1 a.m., he reached an emotional crescendo with his own brief speech against the war: “Arms are being severed. Metal is clashing through human bodies because of the public policy this government and all its branches continue to support.” He then broke down in tears of exhaustion and sorrow and stopped, saying he was “physically incapable of continuing any longer.”

The remaining text of the papers in his possession was entered into the record. On June 30, the high court ruled in favor of the newspapers in a landmark victory for the freedom of the press.

For a time, Mr. Gravel’s display made him a hero of the left. But in the Senate, his behavior — especially his tearful outburst — appalled many members with what they considered a breach of decorum. At his party’s 1972 national convention, he further alienated fellow Democrats by defying custom and seeking support for an unauthorized run for the vice-presidential nomination.

Over the next several years, he saw his fame and popularity erode. He was unseated in the 1980 primary, amid the GOP landslide that ushered Ronald Reagan into the presidency.

Mr. Gravel described the ensuing years as a prolonged “midlife” crisis. “I’d lost my job,” he told The Post in 2007. “I realized that a lot of people I’d regarded as friends were only people who’d wanted to be around me when I had power. Nobody wanted to hire me for anything important. I felt like I was worthless.”

He got divorced from his first wife and failed in a real estate venture. Moving to California, he tried with little success to stir interest in national ballot initiatives conceived in the spirit of greater direct democracy.

Campaigning on his opposition to the U.S.-led invasion of Iraq in 2003, he made a long-shot bid for the Democratic presidential nomination in 2008. He embraced quirky online videos to drum up support. In one, he stares in silence at the camera for a full minute, then chucks a large stone into a pond. As ripples radiate across the water, Mr. Gravel says nothing and walks away.

The televised debates did not give him much airtime, but he landed a few punches, criticizing some of his fellow candidates as supporters of the Iraq War and militarism in general.

At the first Democratic debate in 2007, the 76-year-old Mr. Gravel attracted a flurry of attention for telling Barack Obama, Hillary Clinton, Joe Biden and John Edwards — the “mainline” candidates, as he called them — that they frightened him with their failure to renounce nuclear weapons. The United States, he said, had “no important enemies.”

“Tell me, Barack,” Mr. Gravel said, “who do you want to nuke?”

“I’m not planning to nuke anybody right now, Mike, I promise,” Obama replied, to guffaws.

“Good, good,” Mr. Gravel said. “We’re safe then, for a while.”

After dropping out of the race, Mr. Gravel later lost a bid for the Libertarian Party nomination. He subsequently became chief executive of a medical marijuana company.

Maurice Michael Gravel was born in Springfield, Mass., on May 13, 1930, the third of five children in a French-speaking Quebecois family. He was 7 before he learned English and described himself as a lackluster student who suffered from dyslexia and an “inferiority complex.”

Being recruited to hand out political fliers in high school, he recalled, imbued him with a sense of purpose. “I liked the way people listened when I talked about a candidate,” he told The Post. “It gave me confidence.”

Growing up, he worked alongside his older brothers in their father’s house-painting and general-contracting business. He attended a Catholic boarding school in Worcester, Mass., and then did caddying and janitorial work while attending a local Catholic college.

After Army service in Germany during the Korean War, he received an economics degree from Columbia University in 1956. He then made his way to Anchorage, where he took whatever work he could, selling real estate and, for one winter, working as a brakeman on the Alaska Railroad.

Elected to the Alaska House in 1962, he lost a 1966 race for Congress before defeating U.S. Sen. Ernest Gruening in the 1968 Democratic primary.

Two Senate terms later, Mr. Gravel lost a primary battle with Gruening’s grandson, Clark, who was then defeated in the general election by Frank H. Murkowski, a Republican and future Alaska governor.

Mr. Gravel’s marriage to Rita Martin ended in divorce. In 1984, he married Whitney Stewart. In addition to his wife, of Seaside, survivors include two children from his first marriage, Martin Gravel of Parker, Colo., and Lynne Mosier in Austin; two sisters; four grandchildren; and a great-grandson.

In early 2019, three New York high-schoolers filed official paperwork that effectively drafted Mr. Gravel, then 88, to make another presidential bid. “The goal will not be to win,” he tweeted, “but to bring a critique of American imperialism to the Democratic debate stage.” The effort gained some initial traction online but quickly sputtered out.