Thain White was born in Milburn, Illinois on January 26, 1913, the son of Ernie and Hazel White. In early childhood, the family moved to Rollins, Montana, where Ernie White established a sheep farm called the Columbia Sheep Company. While working for his father and later on the Fort Peck Indian Reservation and in Glacier Park, Thain developed an interest in the history and archaeology of Montana. He conducted archaeological digs with Carling Malouf, Gordon L. Pouliot, and Duane Hampton, developing precise documentation for the sites. Among the sites he explored were the Big Hole Battlefield, the Bear's Paw Battlefield, various Mullan Road and Lolo Pass sites, and others.

In 1949 Thane and his father established the Flathead Lake Lookout Museum at Lakeside to display artifacts of local interest. The Museum also sponsored Thane's research and many of his research papers bear the imprint of the museum. In later years he lived at Dayton, where he died April 30, 1999. He was survived by his wife Fay White.