After a childhood spent in New York, Connecticut, and Europe, followed by service in the U.S. Army during World War II, Solley attended Yale University, where he received a BA in architecture in 1950. He began his architectural career as a project engineer for Lilly and Company in Indianapolis, remaining there for 10 years before opening a private architectural practice in 1961.
After working as an architect, Solley was recruited by Henry Hope, who was then director of the IU Art Museum, to begin graduate studies in art history at IU in 1964. He received his MA in 1966, followed by two years of postgraduate study in Modern and Surrealist art. In 1968, he became assistant director of the museum and three years later was named director. Art collector, architect, art historian, and philanthropist, Solley brought all of these talents to bear on his work throughout his 18 years at the IU Art Museum. Under his leadership, the museum's core collection of 4,000 objects grew to a wide-ranging collection of more than 30,000 works of art. He spearheaded and oversaw the museum's move from the Fine Arts Building to the facility designed by I.M. Pei & Partners, dedicated in 1982.
Under Solley's leadership, the museum greatly expanded its collections gaining special excellence in Ancient, African, Oceanic, and Pre-Columbian art, as well as works on paper and photography. Solley's interest in Early Modernism and Surrealism led to further strengths in European art from 1900 to 1930. He also gave generously of his own collections. Solley came from the Indiana family perhaps most renowned for its visionary philanthropy and its art collections, the Lillys. His great uncle, Josiah K. Lilly, founded IU's Lilly Library. In addition to numerous major gifts during his tenure at the museum, in 1996 Solley established the Thomas T. Solley Endowed Fund for the Curator of Ancient Art, followed four years later by his endowment of the Pamela Buell Curatorship of Asian Art.
Among many other honors, he was awarded the first Indiana University Medal in recognition of his extraordinary commitment to the IU Art Museum, presented at the dedication of the museum in 1982. In 2002, the Thomas Treat Solley Atrium of the art museum was named in his honor, and he received an honorary doctorate from Indiana University. Solley retired as director in 1986. He died in April 2006 at his home in St. Prex, Switzerland, following a lengthy illness.
