John Trudell in 1971 after a band of American Indians occupied a remote former Nike site near Richmond, Calif. (Richard Drew)

John Trudell, who was a spokesman for American Indian protesters during their 1969 occupation of Alcatraz Island in California and later headed the American Indian Movement, died Dec. 8 at his home in Santa Clara County, Calif. He was 69.

The cause was cancer, said Cree Miller, a trustee for his estate.

Mr. Trudell became involved in Native American activism after serving in the Navy in Vietnam. In 1969, he joined American Indians who had occupied Alcatraz Island in San Francisco Bay to demand that the former federal prison be given to Native Americans under treaty rights.

Mr. Trudell, who studied radio and broadcasting at a community college in San Bernardino, Calif., became a spokesman for the group that called itself the United Indians of All Tribes, and he ran a radio broadcast from the island called Radio Free Alcatraz.

The protest eventually dwindled, and the last demonstrators were removed by federal officers after 19 months.

John Trudell in 2005. (Bryan Bedder)

Mr. Trudell went on to serve as national chairman of the American Indian Movement from 1973 to 1979. His FBI dossier from that era called him “extremely eloquent and therefore extremely dangerous.”

In 1979, while Mr. Trudell was demonstrating in Washington, his pregnant second wife, Tina Manning, their three children and his mother-in-law were killed in a fire at Manning’s parents’ home on the Duck Valley Indian Reservation in Nevada.

Mr. Trudell and others long suspected government involvement, but the cause of the fire was never determined.

“It left me even angrier than I was — and I was never too calm to begin with,” he later told the New York Times. “Between the years 1979 and 1984, I drove 250,000 miles. I just ran it out.”

Mr. Trudell drifted away from Indian activism and took up environmental advocacy and ­anti-nuclear energy causes. He also took to poetry, calling poems his “hanging-on lines,” and he put his words to music initially in collaboration with Jesse Ed Davis, an American Indian guitarist who had worked with Bob Dylan and singer Jackson Browne.

After Davis died in 1988, Mr. Trudell said Dylan encouraged him to continue as a solo artist.

“He told me that what I was doing with music was revolutionary,” Mr. Trudell told the New York Times. “And he said to stay with it — don’t change a thing, stay after it. That was encouraging because there were definitely some stretches that were like looking down a long tunnel. . . . I’m basically a starving artist, but that’s got to change.”

Mr. Trudell combined spoken words and music on more than a dozen albums, including one released earlier this year. His fans included Kris Kristofferson, who paid tribute to Mr. Trudell with the 1995 song “Johnny Lobo,” a tune Kristofferson still frequently performs live.

John Trudell was born in Omaha, on Feb. 15, 1946. His father was Santee Sioux, and Mr. Trudell grew up partly on the Santee Sioux Reservation after his mother died.

His first marriage ended in divorce around the time of the Alcatraz protests. Mr. Trudell later had a relationship with Marcheline Bertrand, the mother of actress Angelina Jolie, before her 2007 death from cancer. She was an executive producer of a 2005 documentary about him called “Trudell.”

Mr. Trudell acted in several movies, including “Thunderheart” (1992) starring Val Kilmer and “Smoke Signals” (1998) starring Adam Beach. He also appeared with his friend Steven Seagal in “On Deadly Ground” (1994).

In 2012, Mr. Trudell and singer Willie Nelson co-founded Hempstead Project Heart, which advocates for legalizing the growing of hemp for industrial purposes as a more environmentally sound alternative to crops used for clothing, biofuel and food.