On 28th February 2020, Professor Maciej Nałęcz was elected Chairman of the Nencki Foundation Council. Professor Maciej Nałęcz was one of the initiators of establishing the Marceli Nencki Foundation. From the beginning of its creation in 2012, he was one of the Founding Members of the Nencki Foundation Committee.

Maciej Nałęcz has been associated with the Nencki Institute since 1976. He obtained the title of professor in 1994, in 1988-1990 was the Deputy Director for General Affairs, and during 1990-2001 held the position of the Director of the Nencki Institute, elected three times. He is the author or co-author of more than 140 publications in scientific journals, books, and serial editions, including experimental papers and reviews (71with IF), as well as science popularization and science policy articles.  Maciej Nalecz has been awarded a number of medals, of which the most important being the Knight's Cross (1995) and the Officer's Cross (2008), the Order of “Polonia Restituta”. He is a member of the Polish Academy of Art and Sciences (PAU) and the European Academy of Science, Arts and Literature. In 2003 he was awarded an honorary doctorate of the University of Artois (Lille, France). Maciej Nalecz has held several positions in international scientific organizations, of which the most important was chairing the Fellowships Committee of FEBS (2001-2010). In 2001, Maciej Nalecz was appointed Director of the Division of Basic and Engineering Sciences at UNESCO in Paris, where he worked until the end of 2015. While with UNESCO, he created the International Basic Sciences Programme, the sole programme dedicated to the basic sciences within the UN System (IBSP), and he was the Executive Secretary. IBSP created, e.g., the first centre for structural studies in Africa and Middle East under UNESCO auspices (synchrotron “SESAME”) in Jordan, the project directly coordinated by M. Nalecz, He was also responsible, on behalf of UNESCO, for the program "For Women in Science" sponsored by L'Oreal, coordinated a number of "International Years" (2005-Physics, 2011-chemistry, crystallography-2014, 2015-light) and UNESCO cooperation with other scientific organizations.