Born in Argentina, Knobel immigrated to Brazil with his family in 1976, at the age of 8, when his father was expelled by the military dictatorship from the position he held at the University of Buenos Aires. As a scientist, Knobel is a pioneer in the field of magnetism, having led an internationally recognized research group whose research had applications ranging from magnetic recording systems to nanomedicine.

Knobel was the 12th rector of the University of Campinas (Unicamp), in Brazil. He is also dedicated to science communication, having founded Unicamp’s Science Exploratory Museum and conducted research on the public perception of science and higher education. He is a member of the Brazilian Academy of Sciences and the Academy of Sciences of São Paulo State (ACIESP).

He has received the José Reis Prize for Science Popularization (CNPq); the CBMM Prize for Science and Technology; the Young Scientist Prize from TWAS Latin America and the Caribbean Regional Partner; and has been awarded the Brazilian Commander of the Order of Scientific Merit, among others. He was a TWAS Young Affiliate (2007–2011) and is now a TWAS Alumnus. In November 2024 he was named a TWAS Fellow, and his election will be effective starting on 1 January 2025.

Since 8 December 2024, Marcelo Knobel is the TWAS Executive Director. He is also responsible for coordination with the associated organizations hosted by the Academy—the Organization for Women in Science for the Developing World (OWSD) and the InterAcademy Partnership (IAP).