Dai was born in Taiwan. He completed a BSc in chemistry at National Taiwan University in 1974, following military service, and went to the United States in 1976 for graduate studies. He obtained his doctorate in chemistry from the University of California at Berkeley in 1981, and then did postdoctoral research at the Massachusetts Institute of Technology until 1984. That year he began teaching in the chemistry department of the University of Pennsylvania in Philadelphia, where he remained for twenty-two years and became department chair and the Hirschmann-Makineni Professor. He founded the Penn Science Teacher Institute that eventually trained 300 in-service science teachers and was named as a model for training science teachers in a 2005 National Academy of Sciences white paper. In 2007 he became Dean of the College of Science and Technology of Temple University, also in Philadelphia, Pennsylvania, and was Provost of Temple University during 2012 - 2016. During his time as provost, Temple's USNWR ranking went from #135 to #115 and Temple became a Carnegie R1 Highest Research Activity University. In 2017, Dai was appointed  vice president for International Affairs at Temple University.