Pietro Majno obtained a doctorate in medicine from the University of Milan in 1986. After basic surgical training in the United Kingdom (FRCS Engl.), he joined the HUG Division of Surgery in 1992. He also completed further training in hepatobiliary surgery and liver transplantation in Paris in 1996 and 1997. Appointed associate professor in the Department of Surgery at the UNIGE Faculty of Medicine in 2010, he was part of the adult and paediatric liver transplant team at the HUG until 2018.

He was then appointed full professor of surgery at the University of Italian Switzerland (USI), and Head of Department at the Lugano Regional Hospital, while retaining his professorship in Geneva. His main interests are in hepatocellular carcinoma surgery (for which he was awarded the Swiss Society of Transplantation and HUG clinical research prizes in 2009), liver metastasis surgery, and segmental transplants with living donors or split livers. He is actively involved in university and community life, particularly in the areas of Planetary Health health, which he will continue to teach at the USI in collaboration with the UNIGE team over the next few years. He is appointed Emeritus Professor in October 2025.