جامعة بيرزيت
Kassis studied in Germany and Lebanon, earning a master's degree from the University of Mainz, and a PhD from the American University of Beirut, both in nuclear physics. He taught physics at a number of universities in Germany, Italy, France, England, Lebanon, and Jordan before joining Birzeit University in 1980. He served as President of Birzeit University from 2004 to 2010.