Thierry Pech holds a degree in modern literature from the École normale supérieure in Fontenay-Saint-Cloud. From 1997 to 2001 he was deputy secretary of the IHEJ, before working as a deputy adviser for the CFDT. In 2002, he became an editor at Editions Seuil, before joining Alternatives économiques magazine in 2009, where he was editorial director. After this experience, in 2013 he became managing director of the Terra Nova Foundation, and in 2019 will co-chair the Citizens' Climate Convention announced after the Great National Debate.