Klaus Fleischer was born in Regensburg in July 1939. He completed his studies in medicine at the Universities of Würzburg, FU Berlin, London and Edinburgh. From 1969 to 1977 he worked as a mission doctor in Nigeria, Ghana and Zimbabwe. In 1986 he was appointed chief physician for tropical medicine at the Missionary Medical Clinic in Würzburg, where he also chaired the institute until 2007.
He has received important honors, among others. honorary membership of the German Society for Tropical Medicine and International Health in 2004.
Since 1982 he is an enthusiastic rowing member of the Academic Rowing Club Würzburg.