Leopold is originally from the Philippines but has been living in Europe since starting graduate studies in 1992. He obtained his PhD (1997)  from the Department of Medical Biochemistry and Biophysics at the Karolinska Institute, was an EMBO postdoc fellow at the Max Planck Institute for Biochemistry, Germany and then joined the lab of Prof Dame Carol V. Robinson at the Universities of Oxford and Cambridge, UK. In 2004, Leopold moved to Stockholm University as an Assistant professor and became Docent in 2009. He is a Board member of the Swedish Mass Spectrometry Society and an Editorial Board member of Scientific Reports.