He Dog took part in the Great Sioux War of 1876. When the United States was unable to get control of the Black Hills, the President had a message sent to the northern bands to come in or be forcibly taken in by the U.S. army. He Dog was encamped with the Soreback Band at the time the ultimatum was delivered. He Dog's brother, Short Bull, said that most of the northern Oglala resolved to comply and head in to the Red Cloud Agency in the spring of 1877.

In 1876, He Dog married a woman named Rock and with the Soreback Band, stopped briefly in Wyoming Territory. That spring, a group of troops under Colonel Joseph Reynolds attacked the band, essentially starting the Great Sioux War.

During the summer of 1876, He Dog took part in the Battle of Little Bighorn. He eventually surrendered to American troops at the Red Cloud Agency with Crazy Horse in the spring of 1877. After Crazy Horse was killed, He Dog accompanied the Oglala to Washington, D.C. as a delegate to meet the President.

He Dog left the Red Cloud Agency after its relocation to the Missouri River during the winter of 1877. He joined Sitting Bull in Canadaian exile over the next two years. He Dog and the northern Oglala were ultimately transferred to the Pine Ridge Reservation in the spring of 1882, where he lived the rest of his life. He Dog died in 1936.