Dr. Weiss has collected coins for over 50 years and has specialized in ancient coins for the past 36 years. He is the founder of Nomos AG in Zürich, Switzerland and serves as Chair of the Board. He represents the interests of Nomos AG in the Americas. A Life Fellow and former Trustee of the American Numismatic Society, he has donated numismatic objects to the Society as well as to other institutions such as the National Gallery of Art (Washington, D.C.) and the RISD Museum of Art (Providence, RI).

He specializes in ancient Greek coinage with a specific interest in archaic and early classical coins and has authored several articles in academic publications such as the Numismatic Chronicle, Swiss Numismatic Review, Quaderni Ticinesi and the ANS BCD Festschrift. While he has most often sold high quality coins to collectors and dealers, he has also sold to venerable institutions such as the Harvard Art Museum, The Firestone Library at Princeton University, the National Gallery of Art (London), among others.

His non-numismatic profession is as a hand surgeon. He serves as Professor of Orthopaedics at both Brown University and the Medical University of South Carolina. With over 230 peer-reviewed published articles, over 30 US patents and the author of a major two-volume textbook on hand surgery, his special interest is in complex wrist and finger joint replacement surgery with patients from all over the USA and overseas.