Follonier is a youth exponent from Sion and started playing for their Under-21 squad in the fourth-tier 1. Liga in the 2011–12 season. He made his Swiss Super League debut at 18 May 2014 against Grasshopper in 3-1 home win.[2] In July 2018, after appearing in 14 matches and having scored 1 goal for Luzern,[3] he signed for Servette on loan.[4]
On 2 October 2023, Follonier and SC Cham terminated the contract for personal reasons.[5]