Marco De Bellis founded his law firm in Milan in November 1987. The firm was initially located at Via Freguglia 8, Milan, and moved to its current premises at Via San Barnaba n.30 in January 1, 1989.

Since its inception, the firm has specialized in employment and labour law. This specialty is shared by all 8 qualified lawyers making up the group "Marco De Bellis & Partners", as it came to be known following its reorganization on January 1, 2000.