Born around 1831 on the Grand River in present-day South Dakota, at a place the Lakota called "Many Caches" for the number of food storage pits they had dug there, Sitting Bull was given the name Tatanka-Iyotanka, which describes a buffalo bull sitting intractably on its haunches. It was a name he would live up to throughout his life.

As a young man, Sitting Bull became a leader of the Strong Heart warrior society and, later, a distinguished member of the Silent Eaters, a group concerned with tribal welfare. He first went to battle at age 14, in a raid on the Crow, and saw his first encounter with American soldiers in June 1863, when the army mounted a broad campaign in retaliation for the Santee Rebellion in Minnesota, in which Sitting Bull's people played no part. The next year Sitting Bull fought U.S. troops again, at the Battle of Killdeer Mountain, and in 1865 he led a siege against the newly established Fort Rice in present-day North Dakota. Widely respected for his bravery and insight, he became head chief of the Lakota nation about 1868.

Sitting Bull's courage was legendary. Once, in 1872, during a battle with soldiers protecting railroad workers on the Yellowstone River, Sitting Bull led four other warriors out between the lines, sat calmly sharing a pipe with them as bullets buzzed around, carefully reamed the pipe out when they were finished, and then casually walked away.

The stage was set for war between Sitting Bull and the U.S. Army in 1874, when an expedition led by General George Armstrong Custer confirmed that gold had been discovered in the Black Hills of Dakota Territory, an area sacred to many tribes and placed off-limits to white settlement by the Fort Laramie Treaty of 1868. Despite this ban, prospectors began a rush to the Black Hills, provoking the Lakota to defend their land. When government efforts to purchase the Black Hills failed, the Fort Laramie Treaty was set aside and the commissioner of Indian Affairs decreed that all Lakota not settled on reservations by January 31, 1876, would be considered hostile. Sitting Bull and his people held their ground.

In March, as three columns of federal troops under General George Crook, General Alfred Terry and Colonel John Gibbon moved into the area, Sitting Bull summoned the Lakota, Cheyenne and Arapaho to his camp on Rosebud Creek in Montana Territory. There he led them in the sun dance ritual, offering prayers to Wakan Tanka, their Great Spirit, and slashing his arms one hundred times as a sign of sacrifice. During this ceremony, Sitting Bull had a vision in which he saw soldiers falling into the Lakota camp like grasshoppers falling from the sky.

Inspired by this vision, the Oglala Lakota war chief, Crazy Horse, set out for battle with a band of 500 warriors, and on June 17 he surprised Crook's troops and forced them to retreat at the Battle of the Rosebud. To celebrate this victory, the Lakota moved their camp to the valley of the Little Bighorn River, where they were joined by 3,000 more Indians who had left the reservations to follow Sitting Bull. Here they were attacked on June 25 by the Seventh Cavalry under George Armstrong Custer, whose badly outnumbered troops first rushed the encampment, as if in fulfillment of Sitting Bull's vision, and then made a stand on a nearby ridge, where they were destroyed.

Public outrage at this military catastrophe brought thousands more cavalrymen to the area, and over the next year they relentlessly pursued the Lakota, who had split up after the Custer fight, forcing chief after chief to surrender. But Sitting Bull remained defiant. In May 1877 he led his band across the border into Canada, beyond the reach of the U.S. Army, and when General Terry traveled north to offer him a pardon in exchange for settling on a reservation, Sitting Bull angrily sent him away.

Four years later, however, finding it impossible to feed his people in a world where the buffalo was almost extinct, Sitting Bull finally came south to surrender. On July 19, 1881, he had his young son hand his rifle to the commanding officer of Fort Buford in Montana, explaining that in this way he hoped to teach the boy "that he has become a friend of the Americans." Yet at the same time, Sitting Bull said, "I wish it to be remembered that I was the last man of my tribe to surrender my rifle." He asked for the right to cross back and forth into Canada whenever he wished, and for a reservation of his own on the Little Missouri River near the Black Hills. Instead he was sent to Standing Rock Reservation, and when his reception there raised fears that he might inspire a fresh uprising, sent further down the Missouri River to Fort Randall, where he and his followers were held for nearly two years as prisoners of war.

Finally, on May 10, 1883, Sitting Bull rejoined his tribe at Standing Rock. The Indian agent in charge of the reservation, James McLaughlin, was determined to deny the great chief any special privileges, even forcing him to work in the fields, hoe in hand. But Sitting Bull still knew his own authority, and when a delegation of U.S. Senators came to discuss opening part of the reservation to white settlers, he spoke forcefully, though futilely, against their plan.

In 1885 Sitting Bull was allowed to leave the reservation to join Buffalo Bill's Wild West, earning $50 a week for riding once around the arena, in addition to whatever he could charge for his autograph and picture. He stayed with the show only four months, unable to tolerate white society any longer, though in that time he did manage to shake hands with President Grover Cleveland, which he took as evidence that he was still regarded as a great chief.

Returning to Standing Rock, Sitting Bull lived in a cabin on the Grand River, near where he had been born. He refused to give up his old ways as the reservation's rules required, still living with two wives and rejecting Christianity, though he sent his children to a nearby Christian school in the belief that the next generation of Lakota would need to be able to read and write.

Soon after his return, Sitting Bull had another mystical vision, like the one that had foretold Custer's defeat. This time he saw a meadowlark alight on a hillock beside him, and heard it say, "Your own people, Lakotas, will kill you." Nearly five years later, this vision also proved true.

In the fall of 1890, a Miniconjou Lakota named Kicking Bear came to Sitting Bull with news of the Ghost Dance, a ceremony that promised to rid the land of white people and restore the Indians' way of life. Lakota had already adopted the ceremony at the Pine Ridge and Rosebud Reservations, and Indian agents there had already called for troops to bring the growing movement under control. At Standing Rock, the authorities feared that Sitting Bull, still revered as a spiritual leader, would join the Ghost Dancers as well, and they sent 43 Lakota policemen to bring him in. Before dawn on December 15, 1890, the policemen burst into Sitting Bull's cabin and dragged him outside, where his followers were gathering to protect him. In the gunfight that followed, one of the Lakota policemen put a bullet through Sitting Bull's head.

Sitting Bull was buried at Fort Yates in North Dakota, and in 1953 his remains were moved to Mobridge, South Dakota, where a granite shaft marks his grave. He was remembered among the Lakota not only as an inspirational leader and fearless warrior but as a loving father, a gifted singer, a man always affable and friendly toward others, whose deep religious faith gave him prophetic insight and lent special power to his prayers.