Born in Malta in 1966, Guillaumier moved to Milan to study industrial design at the Istituto Europeo de Design in 1989 and later undertook a Masters in Industrial Design at Milan's Domus Academy. Following an apprenticeship at the design firm, Baleri, he began collaborating with the Architect and Designer Rodolfo Dordoni, specialising in product design and design development. He designed his first products for Foscarini and Mito in 1994.
Between 1995 and 1998 Guillaumier worked for the design firm Driade and was responsible for the strategy and design development of the Atlantide and Dhouse collections.
Since 1998, Guillaumier has been active as a Designer of furniture, lighting, electrical appliances for companies throughout Italy as well as interntionally including Bosa, CasaMilano, DeVecchi, Desalto, Elica, FontanaArte, Foscarini,Montina, Minotti, MG Italy, Nobili, Pamar and Varaschin.
His works are regularly reviewed in Italian and International design journals.