Didier Grandpré started his career in 1993 in a subsidiary of Alcatel as a Sales Engineer, before becoming Head of Motorway activities for telecom transmission equipment in 1998. He then joined the Alcatel group in 2001 as Senior Internal Auditor. In 2004, he joined the information systems department. He was later responsible for the integration of the main European units into a common IT financial management tool. In 2007, when Alcatel and Lucent merged, he was appointed Head of Financial Transformation for the Europe and South regions. Then, in 2009, he defined and implemented Alcatel-Lucent's new business model.

In 2011, he moved to the position of Production and Logistics Controller before moving to supply chain control. In 2014, he was promoted to Director of Group Financial Planning and Analysis. With the integration of Alcatel-Lucent into Nokia, he was appointed, "process owner" for the definition and deployment of processes and applications for management control, forecasting, reporting and analysis. He joined Elior Group in August 2018, as Director of Financial Control, before being appointed Deputy Administrative and Financial Director on March 01, 2023.