Cheng received his BS in Chemistry at Xiamen University in 1984 and subsequently continued his Ph.D study at the Ohio State University from 1985-1990.  He single handedly completed the first total synthesis of the stemona alkaloid, stenine.  He then joined Process Chemistry department at Merck Research Laboratories and worked till the end of 2013.  In 2014, he joined Janssen Pharmaceuticals of JNJ in Switzerland as scientific advisor.  In 2019, Cheng returned to San Diego and joined Mirati Therapeutics as the head of Chemical Processing R&D.  He is currently leading a group of 10 process chemists and is responsible for all the activities related to the drug substances.