cadres Ismaël Emelien and Benjamin Griveaux, as well as HEC alumnus Stanislas Guerini, O participated in the campaign team of Dominique Strauss-Kahn for the 2006 French Socialist Party presidential primary.

[9] After serving as political adviser to finance minister Pierre Moscovici,[5] during the presidency of Socialist François Hollande, O was appointed treasurer of the La République En Marche!

[10] Also since November 2017, O has been part of LREM's executive board under the leadership of the party's successive chairmen Christophe Castaner and Stanislas Guerini.

"[12] Cédric O convinced Facebook to allow French regulators to investigate the company's moderation processes,[13][14] and also arranged a meeting between Macron and Mark Zuckerberg.

[16] Amid efforts to contain the COVID-19 pandemic in France, O was one of the early supporters of the government's proposal for a state-supported “StopCovid” contact-tracing app project.