He was educated at Leningrad State University and graduated in Theoretical Physics in 1971 under the supervision of Academician Vladimir Perel. He left the Soviet Union in 1975 and received his doctorate from Uppsala University in 1978 under the supervision of Erik T. Karlsson.
Tendler moved to the Alfven Laboratory of the Royal Institute of Technology (Kungliga Tekniska Högskolan) as an Associated Professor in 1981 and gradually shifted his interest towards Fusion research. From 1992 until 2002 he was an invited professor at the Institut national de la recherche scientifique, Université du Québec, Canada. He became Full Professor at Kungliga Tekniska Högskolan in 2001.
He is the former President of International Congress on Plasma Physics.
In 2011 he became the Senior science expert at International Thermonuclear Experimental Reactor. Tendler serves on the Advisory Committees of National Institute of Fusion in Toki (Japan), the Institute of Plasma Physics of the Chinese Academy of Sciences and Saint St. Petersburg State Polytechnic University. In the 70s Tendler focused on kinetic and statistical properties of gases and plasmas.
Over time his research shifted towards thermonuclear fusion and has contributed to crucial issues like magnetic confinement and operation scenarios. In particular he has been instrumental in the theoretical understanding of Plasma rotation and L-H confinement mode transitions.
In latter years his research interests broadened into applications of Plasma physics, such as waste treatment.
Member human rights committee American Physical Society, Anaheim, California, 1989. Member Swedish committee Freedom of Science, Stockholm, 1976-1998. Lecturer on human rights, Anaheim, 1989.
Member Swedish Physical Society (chairman plasmaphysics division since 1996), Plasma Physics Division European Physical Society (board directors since 1999).
Married Anna Maria Taubes, July 2, 1980. Children: Cecilia, Salomon.