Livio Castiglioni was the eldest of three brothers, studied architecture at Milan Polytechnic until 1936. In 1938 Livio Castiglioni and his brother Pier Giacomo opened a practice on the Piazza Castello in Milan. Since architects were receiving very few commissions at that time, the Castiglioni brothers concentrated primarily on designing objects for daily use, furniture, and appliances.

In 1939 they designed "Phonola", the first radio encased in Bakelite instead of wood. After finishing his studies, the youngest of the three, Achille Castiglioni, joined his brothers in the practice in 1944. Livio Castiglioni went his own way from 1952. Between 1940 and 1960 Livio Castiglioni was a design consultant for Phonola and, from 1960 until 1964, for Brionvega. All three brothers were very active in the Italian design scene. In 1956 they were co-founders of the Associazione per il Disegno Industriale (ADI), the Italian Industrial Design Association which awards the coveted and important Compasso d'Oro.

In 1959-60 Livio Castiglioni was president of the ADI. The designer object for which Livio Castiglioni is best known is "Boalum", a lamp he designed with Gianfranco Frattini for Artemide in 1971. This serpent-like lamp consists of a white, flexible plastic tube, two meters long, in which several lights are inserted in a row. Up to four lights can be linked together at the end pieces to make a light fitting up to eight meters long, which can be intertwined as desired.