[4] He began his career in 1967 at the National Center for Telecommunication Studies, where he worked on the development of new products related to satellite and mobile systems.

As France Telecom's chairman and chief executive officer, Didier Lombard continued the group reorganization policy initiated by Thierry Breton.

[6] The reorganization project presented and implemented by Lombard saw the suppression of 22,000 posts and the mobility of 10,000 workers over three years (2006–2008).

[9] His trial began in May 2019,[10] and in December 2019, he was found guilty and sentenced to one year in prison, of which 8 months suspended and to a €15,000 fine.

[11] Lombard assumed the chairmanship of the supervisory board of ST Microelectronics, a French-Italian semiconductor group of which he has been a director since 2004.