RNDr. František Lehar was born on 9th August 1934 in Bludov, a village nearby the city Šumperk (North Moravia), in the house built by his grandfather, director of primary school in Bludov. He spent his childhood and youth in Prague; his father, also RNDr. František Lehar, was director of the grammar school „First Masaryk Gymnasium“ in Křemencova street. His son František studied this grammar school up to the year 1948 when it was canceled, and then he continued to study another grammar school, „Academic Gymnasium“ in Štěpánská street; he passed here a school-leaving examination with honors in 1952. After it the started to study nuclear physics on the Faculty of Mathematics and Physics of the Charles University; he finished his study with honors five years later. Then he started to work as the assistant on the Faculty of Technical and Nuclear Physics of the Charles University, and three years later he was promoted to the rank „assistant profesor“. In 1961 he left to the Joint Institute of Nuclear Researches (JINR) in Dubna (Russia, Moscow region) where he worked for seven years. In this institute he defended his PhD thesis on the theme “Neutron scattering on protons at energy of 630 MeV”.

In 1959 he married Lilian Štaffová. She died in 1999; three years later in 2002 he married a second time with Libuše Paukertová.

During his stay in the JINR he within his holidays took part in several climbs on peaks of Caucasus, Tian-shan and Pamir. In 1965 he took part on the five-member expedition which climbed the Pik Lenina (7 134 meters above sea level).

In August 1968 he went into exile. First he worked in the CERN by Geneva, and then in the French Institute of Nuclear Research (owner oif which is the „Commissariat à l´Energie Atomique“) in Saclay nearby Paris as a researcher, and later as a director of research of the CNRS (National Center of Scientific Research).There he was active until 1999, then he continued his work as a consultant untill 2009. As an employer of the CNRS he participated on experiments and conferencies in various laboratories and institutes all over the world. In 1974 he received the French citizenship; after the year 1990 he also received back the Czech citizenship. In 1974 he was appointed a member of the Scientific Council for construction and planning experiments on the new, very progressive accelerator „Saturne 2“. Under his leadership has been built a complex experimental apparatus which allowed to measure characteristics of the scattering of polarized beams of nucleons on polarized nucleons in a broad range of energy. He also participated on similar experiments in another institutes - the CERN, the Paul Scherer Institute in Villigen (by Zürich, Switzerland), and the Fermi National Laboratory by Chicago, USA. Original results of these researches are summarized in more that 300 scientific publications issued on both sides of the Atlantic, in Japan, and elsewhere. He is considered one of the leading researchers in elementary particle spin physics.

RNDr. František Lehar always tried to develop contacts between physicists from East and West, mainly after the fall of the Iron Curtain. Thanks to his initiative, an important equipment and literature was donated from Saclay to the JINR Dubna and to institutes in Prague (Faculty of Mathematics and Physics of the Charles University, Faculty of Nuclear Sciences and Physical Engineering of the Czech Technical University). This equipment allowed to obtain top results in the field of spin physics at accelerators in the JINR Dubna. In 1993, RNDr. František Lehar was appointed a member of the Scientific Council of the JINR; this position he held up to 2010.

On 23th April 1996, the Czech Technical University in Prague awarded him rank and rights of honorary Doctor of Physical and Mathematical Sciences for excellent results in the field of nuclear physics, for long-time successful cooperation with the Czech Technical University and for valuable contribution to the integration of Czech science in an international context. Thus he became one of significant persons whom this honor has been given in the past. In 2002 he was appointed a member of the Scientific Council of the newly established Institute of Applied and Experimental Physics of the Czech Technical University in Prague. In this institute he worked until his death on the 23rd November 2011.