Clea Koff, who is mixed-race and Jewish, was born in 1972 to a Tanzanian mother and an American father, both documentary filmmakers focused on human rights issues. Her parents took her and her older brother, Kimera, with them around the world. She spent her childhood in England, Kenya, Tanzania, Somalia, and the United States.

By the time she was a teenager she had decided to study human osteology, which she did first in California. She earned her bachelor’s degree in anthropology from Stanford University. Koff then went on to the master's program in forensic anthropology at the University of Arizona. She completed her masters degree in 1999 at the University of Nebraska-Lincoln, after combining her studies with working for the UN between 1996 and 2000.

As a 23-year-old graduate student studying prehistoric skeletons in California, Koff joined a small team of UN scientists exhuming victims of the genocide in Rwanda. Her job was to find evidence to bring the perpetrators to trial, and to help relatives to identify their loved ones. Koff captured the events in her memoir The Bone Woman, which was published in 2004.