Dennis Banks, whose Ojibwa (Chippewa) ancestors’ names were not registered on a ship’s manifest, was looking to put down roots. Born on a reservation in Minnesota, Banks was shipped off by the Bureau of Indian Affairs to a boarding school at age 5, the better to erase his heritage. When he returned home after 11 years, his mother had moved and started a new family.

In 1968, after a stint in the Air Force in Japan that ended with Banks going AWOL, and two and a half years in jail on a burglary rap, he helped found the American Indian Movement (AIM) to advance the interests of Native Americans.

Having renounced alcohol, Banks made his way to the Pine Ridge reservation in South Dakota. He asked a medicine man there to indoctrinate him in Lakota rituals. Banks was desperate to connect to a tribal past; he wasn’t about to quibble over which tribe’s. He began regularly practicing rituals of smudging, singing at the drum, pipe carrying and religious use of tobacco. He insisted on a spiritual component to AIM as well. He promoted sweat lodges and sun dances, in which flesh was pierced and suffering endured, as a means of transforming alienated youth into warrior priests.

The rituals inspired community, and so did Banks. He was a charismatic leader, adept at building social networks. Later in life, he coached runners and organized spiritual marathon runs around the world. He also produced a community of his own, marrying four times and fathering 20 children.

AIM’s spiritual communion with the past only underscored the conundrums of its present — how to be fully Indian and fully modern, and how to be American when your Americanness was the very thing, along with the land beneath your feet, that had been stolen from you.

Amid the revolutionary fashion of the early 1970s, AIM’s look was cool — buckskin, braids, feathers, rifles. But while the Black Panthers preached revolution, AIM called for restoration. Its demands were rock-ribbed Republican. It wanted property rights safeguarded, borders enforced, laws respected, debts paid, treaties upheld.

Banks was instrumental in attracting recruits for AIM and connecting them to myth, history and one another. But a realistic vision for the future never jelled. And in a political system that honored wealth and valued votes, Indians, who had been reduced to less than 1 percent of the population, largely impoverished, possessed neither.

In lieu of power, Banks opted for attention, operating a guerrilla theater that used live ammunition. “I think he helped Native Americans realize that they still count and need to step forward and let U.S. society know we are still here,” says John Echohawk, a founder of the Native American Rights Fund.

Banks and his photogenic colleague Russell Means became what The Los Angeles Times called the “most famous Indians since Sitting Bull and Crazy Horse.” There was collective pride in that, along with jealousies, rivalries and subterfuge. When a trusted aid to Banks announced that he was an F.B.I. informant, the government’s counterintelligence work was done: Fear of infiltrators led to suspicion and vengeance.

In a historical inversion, AIM would go on to occupy white property, recouping a symbolic fraction of a bill that was cosmically in arrears. But the endgame, given the lopsided power of AIM’s federal adversaries, was always distant, the staging improvisational. When Banks led a caravan of AIM members to Washington in 1972, the group sat in at the Bureau of Indian Affairs headquarters (and its cafeteria) and refused to leave, in no small part because night was coming and they had failed to secure accommodations.

AIM’s last stand at Wounded Knee, S.D., was similarly ad hoc, a strategic fiasco slathered in media. Hundreds of Lakota were massacred at the site by the United States Army in 1890. Seeking to dramatize local corruption and pervasive injustice and also to honor the dead, AIM moved into the tiny hamlet on the Pine Ridge reservation after minimal planning. Provisions and ammunition soon ran short.

Hundreds of government agents laid siege; AIM held out for 71 days. Two AIM supporters were killed; another’s body was never found. (A suspected F.B.I. mole, he may have been murdered.) A federal marshal was paralyzed.

AIM surrendered, then unraveled. Banks took to life on the run, making an underground tour of 1970s bizarro, with star turns by William Randolph Hearst (who sought Banks’s help finding his kidnapped daughter), Marlon Brando (who supplied Banks with a mobile home and $10,000 for a getaway) and the cult leader Jim Jones (who raised bail for Banks’s wife before leading his followers to mass suicide in Guyana in 1978).

Banks eventually served a short stint in prison on charges unrelated to Wounded Knee. He kept faith with his spiritual renewal and encouraged his own children to draw spiritual strength from rituals and running. But his paradoxes persisted. His preferred nomenclature was “human rights activist,” but his 2004 autobiography was titled “Ojibwa Warrior.” He lavishly extolled the healing powers of native medicine, but he died at the Mayo Clinic.

As AIM prepared to surrender at Wounded Knee and Banks readied an escape through the federal cordon, a Lakota medicine man said a prayer to make Banks invisible. That a 20th century Indian, a defiant survivor, should require such a ministration was achievement in itself.