Dr. Sieber was born in Shawano, Wisconsin, and graduated from the New School for Social Research in New York. He received a master's degree and a doctorate in African art history at the University of Iowa. He joined the faculty at Indiana University in Bloomington and then joined the staff at the Smithsonian in 1983, where he served for 10 years. While at the Smithsonian, Sieber was responsible for evaluating collection research and developing standards for acquisitions. He served as co-curator and co-author of the exhibition and catalogue "African Art in the Cycle of Life" (1987-88), which was the inaugural exhibition of the museum's site on the Mall. After retiring from the Smithsonian, he returned to Indiana University.
Among his publications include catalogues that accompanied exhibitions on the art of northern Nigeria, on African textiles and furniture, and on furniture and household objects, as well as other articles related to African art. He also wrote the introduction to "Selected Works from the Collection of the National Museum of African Art," "Hair in African Art and Culture," and an essay in "Extreme Canvas: Hand-Painted Movie Posters from Ghana."
Throughout his career, Sieber lectured on African art at institutions across the United States and abroad.