Sileshi Semaw (currently a U.S. citizen) was born in 1960 in Addis Ababa, Ethiopia. He completed his undergraduate studies in 1982 with a B.A. in History at Addis Ababa University. Semaw worked as a Historian at the National Museum of Ethiopia for 4 years, after which he succeeded to win a scholarship to study Palaeolithic Archaeology abroad. He completed his Ph.D. in 1997 in Anthropology at Rutgers University in New Jersey. He excavated the oldest stone tools dated to 2.6 million years (Ma) at Gona (Afar, Ethiopia) for his Ph.D. dissertation. Upon completion of his graduate studies, Semaw was offered a Postdoctoral fellowship with the CRAFT, Stone Age Institute, Indiana University, Bloomington, Indiana, U.S.A, where he organized the International and interdisciplinary Gona Palaeoanthropological Research Project. Semaw joined CENIEH in Burgos, Spain in 2011 as a Senior Scientist (within the Prehistory Program) where he is responsible for the study of the first lithic industry.

With a team of archaeologists, geologists and paleontologists, the large scale Gona Project began fieldwork in 1999. Fifteen years of continued investigations at Gona have resulted in the discovery numerous fossil hominins from several critical time intervals in human evolution, including Ardipithecus kadabba (~5.8 Ma), Ardipithecus ramidus (~4.5 Ma), early Homo erectus (~ 1.6-1.5 Ma), late Homo erectus (~ 0.4 Ma), and a recently found Homo sapiens (~0.1 Ma). The Gona archaeology team has documented discoveries illuminating ancestral hominin behavioural evolution from the earliest Oldowan dated to 2.6 Ma up to the recent. In addition, more than thousands of well-preserved and identifiable faunal specimens were documented with the hominin and archaeological discoveries. Semaw and colleagues have published the results of their research in numerous scientific journals including Nature and Science. Currently, he is continuing his research as the Co-Pi of the Gona Project based at CENIEH, Spain.