Thomas Anderson Robertson was born at Grey Cloud Island (presently Washington County, Minnesota) to parents Andrew Robertson (born in Scotland) and Jane (Day Break Woman) Annacinahawin Anderson (a mixed-blood Dakota). His father was the superintendent of schools and an interpreter at the Lower Sioux Agency. Thomas received his education from the missionaries, and later he was employed as an interpreter at the agency. In 1858, he and his father were among the delegation that traveled to Washington, D.C. for the treaty negotiations, where Thomas served as an interpreter. On August 18, 1862, the Dakota, angry with conditions at the reservation, attacked the whites at the Lower Sioux Agency, and at the settlements in the area. By this time, Thomas' father had died (1859) and his mother was living in the Beaver Creek settlement, across the Minnesota River. The Dakota captured his family and forced Thomas to accompany them on attacks at New Ulm and Fort Ridgely. Later, he and another mixed-blood captive, Thomas Robinson, were selected by Chief Little Crow to shuttle messages to and from Colonel Sibley at Fort Ridgely. Following the uprising, he was tried by a military commission for appearing at the battles of New Ulm and Fort Ridgely, but was acquitted. In the winter of 1862-63 he was in the Dakota camp at Fort Snelling, and then went to the Crow Creek reservation in Dakota Territory. By 1865, at the end of the Civil War, he was a corporal in Company L, First Regiment of the Minnesota Heavy Artillery. After the war he was a chief scout in one of the Dakota scout camps that were organized to protect the area settlers in what is now northeastern South Dakota. When the Sisseton-Wahpeton reservation was established in 1867, Thomas moved to the southeast quarter of section 29, Veblen Township, Marshall County, where he farmed 160 acres of land next to the cemetery in which he is buried. He married Ida M. Standfast in 1875. They had six children before she died on January 28, 1909. After Ida's death, he married Nancy Santee. Thomas died near Veblen, South Dakota on January 30, 1924, at age 84.