François Grosdidier is the grandson of an historian and the son of an engineer working in the iron and steel industry of Lorraine.

From 1989 to 1995 (one complete term), he was elected municipal councillor of the city of Metz, seating in the opposition to the mayor, Jean-Marie Rausch.

His regional department covered industrial reconversion, new technologies of information, training and professional learning.

During the 1993 French legislative election, he contested the seat of the 1st constituency of Moselle (departement) (part and north of Metz), a left-wing workers district.

After supporting Jacques Chirac for the 1995 French presidential election, the Prime minister Alain Juppé entrusted him for a parliamentary mission on industrial reconversion.

When Jacques Chirac decided to dissolve the National Assembly in 1997, François Grosdidier lost the election against the candidate of the Socialist Party, in the second round.

During his three terms as mayor, he renovated the city housing and restored security by an increasing of number of police officers.

After his reelection as senator in 2017, he was forced to resign from his office of mayor of Woippy, due to the effective date of the 2014 law banning dual mandate for members of both houses of Parliament.