I met Hamza Akel Hamieh in Beirut in the early nineteen-eighties, after he had hijacked six planes—a record to this day—to draw the world’s attention to the kidnapping of Musa Sadr, his religious leader. One of the hijackings, in 1981, was among the longest in aviation history. He commandeered a Libyan plane midair between Zurich and Tripoli and ordered it on a six-thousand-mile transcontinental odyssey to Beirut, then Athens, Rome, Beirut again, and Tehran, before ending back in Lebanon. Hamieh walked away, free, from all six hijackings. No one was injured or killed.

With his wavy shag haircut and dark beard, Hamieh looked like a taller version of Al Pacino in “Serpico.” He was a legend in the Middle East, famed for his daring and charisma and often compared to Che Guevara. Born in 1954, he was at the side of Ayatollah Khomeini when the revolutionary leader flew back to Iran from exile in Paris, in 1979. He fought in Afghanistan against the Soviets and in the Iran-Iraq War against Saddam Hussein’s Army. When he was still in his twenties, Hamieh became commander of Amal, which was Lebanon’s largest Shiite militia at the time. The honorific “Hamza” was bestowed upon him by fellow-fighters, after the Prophet Muhammad’s uncle, who served as a ferocious fighter in battles to expand the early Islamic empire.

It took me a couple of years to find Hamieh in Beirut’s militia labyrinth, amid the chaos of a civil war and the Israeli occupation. He moved among the front lines. I finally found him at his uncle's home, connected to an intravenous drip, recovering from an injury. Several of his commandos stood around the bed. His six-month-old son, Chamran, was in a nearby hammock, which Hamieh occasionally rocked with his free hand to quiet the child’s crying. We talked for hours about his life and his war stories. He was a case study of how men turn to militancy and violence, and he became a chapter in my first book.

I went back to Lebanon this fall and saw Hamieh again, more than three decades after we'd first met. His hair had turned silver, and he had traded his fatigues and military boots for jeans, a pinkish shirt, untucked, and navy tennis shoes. He’d grown a little paunchy. We talked first in Dahiyeh, a poor southern area of Beirut. A few days later, I visited his home, in the Bekaa Valley, to see his memorabilia. He was recovering from surgery for a brain tumor. Chamran, now an adult with children of his own, stopped by to check on his father’s health.

The first thing I asked was whether Hamieh had hijacked any planes since we last met. He laughed. “No,” he said, though the issue that had spurred all six of his hijackings, carried out between 1979 and 1982, had never been resolved.

Hamieh was part of the first generation of militants, mobilized in the nineteen-seventies, who had been captivated by the utopian illusions promised in the early versions of politicized Islam. The Shiites—Islam’s minority—bought in first, notably in Iran and Lebanon, a decade before their Sunni counterparts.

“Before the civil war, the Shiites in Lebanon were shoeshine boys or trash collectors,” another former Amal fighter, who facilitated the reunion with Hamieh, told me. “To go to college or get a good job, they had to kiss the ass of a Maronite Christian or a Sunni.” Hamieh’s father was a laborer at the airport terminal.

After centuries on the margins of politics, society, and economic life, Lebanon’s Shiites were inspired by Imam Musa Sadr, a magnetic cleric famed for his green eyes. He was born in Iran, of Lebanese descent. (Shiites in the two countries have had unusually strong bonds since the Safavid dynasty converted Persia from Sunni to Shiite Islam, in the sixteenth century; clerics have moved back and forth between them since then.) Sadr moved his family back to Lebanon, and, in the nineteen-sixties, founded the Movement of the Disinherited, which spawned social institutions, clinics, a welfare network, schools, an orphanage, and a new political party under the umbrella of Amal, or “hope” in Arabic.

“Musa Sadr was the Martin Luther King of the Shiites of Lebanon,” Fawaz Gerges, an expert on extremism at the London School of Economics, said, in a documentary on jihadism, in 2013. “What Musa Sadr did was to transform a highly marginalized and disfranchised community like the Shiites into an army of activists. He gave the Shiites political hope and political courage to demand an equal share in the social and political process.” The late Fouad Ajami, of the Hoover Institution, at Stanford, called Sadr a “towering figure” in Shiite thought.

Hamieh, when he was still in his teens, was among Sadr’s early acolytes. Later, as Lebanon’s other major sects mobilized militias and the country disintegrated into civil war, Amal set up an armed wing, and Hamieh was recruited as a fighter. The Hamieh clan had historically been one of Lebanon’s toughest. They came out of the Bekaa Valley, the largest, poorest, and most lawless region of the country.

“Throughout history, the Bekaa was neglected,” Hamieh told me. “Our ancestors were revolutionaries against the [Ottoman] Turks, the French, then Israel’s occupying Army.” Hamieh was exposed to weaponry growing up; he quickly became a marksman himself. He had a particular affection, he once told me, for the Czech-made rocket-propelled grenade. One of Hamieh’s trainers was Mostafa Chamran, a Berkeley-educated Iranian who later became Minister of Defense in the Islamic Republic. Hamieh’s son is named after him.

The hijackings started after Musa Sadr, along with two colleagues, vanished, in 1978. Sadr was on a swing through the Middle East to appeal for support and aid. His last stop was in Libya. He was due to fly next to Italy. His luggage showed up in Rome, but he did not. Five months later, when the Lebanese government, the Islamic world, and the international community had done nothing, Hamieh started hijacking planes to generate attention for the missing spiritual leader of more than a million Lebanese.

“He is our_ _Imam,” Hamieh told Les Bradley, the British pilot of a Kuwait Airways flight, during what was his final hijacking, in 1982. Bradley recounted the ordeal to me after it ended. In conversations with the Beirut airport control tower, Hamieh had demanded that Lebanon sever relations with the regime of Muammar Qaddafi, that the United Nations take up the Sadr case as an urgent issue, and that an international delegation travel to Tripoli to investigate. He vowed, “It is not possible for us to come out of this plane even two months from now, until the Imam Sadr returns safe and sound.”

Bradley recalled how the other young hijackers turned the airplane cabin into a classroom, putting up posters and pictures of Sadr in the aisles and using the public-address system to give lectures to the hundred and five passengers, most of whom did not speak Arabic. Lebanese officials and a prominent Shiite cleric tried to negotiate from the control tower, in between bursts of gunfire back and forth between airport security and Hamieh’s henchmen on the plane. Pleas from Sadr’s sister, as well as pledges by government representatives to take the case to the United Nations, the World Court, and the Arab League, eventually convinced him to abandon the blue-and-white Kuwaiti plane.