Devillé obtained a master's degree in law from KU Leuven and then studied notary law at the Vrije Universiteit Brussel. Professionally, he was a lawyer at the Brussels Bar between 2013 and 2018, and then a real-estate and corporate lawyer as well as working as a legal assistant in a notary office.[1]
Devillé was part of the Nationalistische Studentenvereniging organization as a student where he met future VB leader Tom Van Grieken. In 2003 he joined the Vlaams Blok party which became Vlaams Belang a year later. He was a member of the national board for the Vlaams Belang Jongeren. In 2006, he was elected as a municipal councilor in Halle at the age of 18 and was the youngest councilor elected at the time. He held the position until 2018 when he resigned to take a break from politics for his legal career and because he was moving to Mechelen. However, he also led a legal campaign in Halle to prevent the construction of a new mosque.[2] During the 2024 Belgian regional elections and stood as a candidate in the Flemish Parliament and was elected to the Antwerp constituency.[3]