With a a BA in Economics and Politics from the Université de Montréal and a Master in European Affairs from the Sciences Po School of Public Affairs, Guillem began his career at the French National Assembly, subsequently moving to the European Parliament. During the 2017 French parliamentary elections, he was campaign director for a rural area. He joined the Tilder team in 2018.
Passionate about public affairs, Guillem is vice-president of a political association in his home town of Loiret and volunteers with local elected officials to define their image strategy. He is particularly involved with several candidates in municipal elections in the implementation of their communication and mobilization strategies.