From 1972, Leoš Heger worked at the Radiology Department of the Faculty of Medicine, Charles University, Hradec Králové, as a research assistant, researcher, lecturer and associate professor. In 1991 he became Head of the Clinic of Radiology, University Hospital, Hradec Králové, and in 1993 also Deputy for Preventive Health Care. Between 1996-2009, he worked as Director of the University Hospital of Hradec Králové. He resigned from this post in 2009 upon his own request.

In the 1970´s, he was involved in the introduction of ultrasonography in the field of cardiology and abdominal diagnostics as well as of computer tomography in the Czech Republic. From the 1990´s he also participated in the implementation of quality programmes and other advanced methods in healthcare management in the Czech Republic. In this area, he has been long active as a teacher and lecturer. He has written or co-written 125 works such as scientific opinions, articles, essays, etc. He has also gained foreign experience during his long-term stays in the USA, Kuwait, and Germany.

Before 2009, when he joined TOP 09 Party, he had never been a member of a political party. From 2002 he was involved in regional politics as a member of the City Council of Hradec Králové.

In his free time, he enjoys cycling, mountain biking, swimming and rowing.