He started his professional career at Krakowskie Zakłady Farmaceutyczne “Polfa” (Polfa Kraków Pharmaceutical Works). Later he worked, among others, as the Deputy Director for Economic Affairs at Przedsiębiorstwo Budownictwa Hydrotechnicznego “Energopol-2” - “Hydrotrest” (Hydrotechnical Construction Company), exercising business supervision over the Kraków water supply from Zakład Uzdatniania Wody Raba (Raba Water Treatment Plant). For many years he worked as the Deputy President of the State Fund for Rehabilitation of Disabled People (PFRON) and Deputy President of the National Health Fund (NFZ). Former President of the Management Board of Stalbud Tarnów S.A. in reorganisation. On 1 April 2017 he was appointed the Vice President of the Management Board of Kraków Water.
 
Janusz Wesołowski graduated from the Faculty of Production Economics at the Cracow Academy of Economics (now the Cracow University of Economics), followed by post-graduate Managerial Career studies at the Cracow University of Economics. He still maintains relationship with his Alma Mater, through active cooperation with the Department of Economy and Public Administration of the University of Economics. He completed the Top Management ISO Certificate courses and has the right to sit on Supervisory Boards. He was awarded the Knight’s Cross of the Order of Polonia Restituta.

As part of his professional work, he implements projects in the area of ​​cost optimisation of ancillary activities. His interests include a broad spectrum of processes related to sales organisation and developing and managing customer relationships.

In 2021, Janusz Wesołowski was awarded the “Krakowskie Dukaty” (Ducats of Krakow) award in the Company Manager category.