Studied at the Faculty of Eelctrical Engineering in Brno, then attended postgraduate study at UK Bratislava (Slovakia) – field: “Nuclear Power Engineering and Environment“. In 2004 he finished studies at the Prague International Business School and gained the title MBA.
From 1974 till 1982 Aleš John was empolyed as physicist and nuclear electronic engineer at the Health Care Institute in Třebíč. From 1982 he was operating engineer of the division of Radiation Safety and Deputy Director o fthe Nuclear Power Station Dukovany (ČEZ Division). In 1988 he was appointed Director of the Nuclear Power Station Dukovany.
From 2003 Aleš John was, within the ČEZ Division, director of the section „“Organisation and Control of the section of nuclear power stations“ and from 2004 till 2008 deputy director of the ČEZ Production Section.
In 2005 he represented ČEZ at the FORATOM in Brussels. From 2008 till 2013 Aleš John was Director General and Chairman of the Board of the ÚJV (Nuclear Research Institute) Řež company (ÚJV Řež).
At present Aleš John deals with independent consultancy in the field of nuclear power engineering and is the chairman of the Civic Safety Committee of the Nuclear Power Station Dukovany (OBK JE Dukovany). From 1999 Aleš John is a member of the Academy of Engineering of the Czech Republic,