Born in Lissone in the heart of what was to become one of the world's most important furniture districts, he trained in his father's carpentry workshop, where he learned many of the crafts' secrets. He attended a course in industrial design at Castello Sforzesco, taught by professors from the Milan Polytechnic, including Tito Agnoli, former assistant to Gio Ponti and Carlo De Carli. At the time, he was employed in the technical department of Besana Mobili, while two years later, he was responsible for the research and development division at Boffi Cucine.

In 1971, he began his career as an independent designer in the A&D, Architecture and Design Studio with Luigi Massoni and Abelardo Pelizza. With Massoni, he designed such pieces as the Esquire leather armchair for Matteo Grassi and other products for prestigious brands like Poltrona Frau, Poliform, Nazareno Gabrielli, to name but a few. In 1991, after the dissolution of A&D, he opened an office in Lentate sul Seveso, where he is still based today. In 1995, awards and recognitions began to arrive. The Mariposa chair by Atlantis was proclaimed Chair of the Year by Promosedia at the International Chair Exhibition in Udine and received an honourable mention at BIO in Ljubljana. The Bloom armchair by Living Divani was selected for the first edition of the Red Dot Design Award. The Lips chair by Dema won the Good Design Award in 2004. His experimental approach helps him find innovative technical solutions, expressed in clean lines and light, airy volumes. Structures in curved plywood, seamless metal, or even sheet steel, testify to his profound knowledge of materials and production techniques.

Cazzaniga's long and fruitful collaboration with MDF Italia gave life to the m1 chair, the Lofty and Sign collections, and the Bora Bora modular sofa collection, nominated for the Interior Innovation Award in Cologne in 2008. From 1999 to 2012, he collaborated with his son Michele Cazzaniga, also a designer, with whom he designed the Tense table collection for MDF, Honorable Mention at the Compasso d'Oro ADI in 2011; the Reader armchairs for Living Divani; and the award-winning Sail chair collection for Andreu World. He also designed the Flexa chairs for the same Spanish company, which won the Red Dot Award 2013, and another award-winning system, the Kobe chairs, for Desalto. Collaboration with Composit resulted in the Touch and Linea kitchens. In 2017, he created Sign Filo, a reinterpretation of the iconic Sign chair by MDF, in which he took his characteristic process of subtraction to the extreme.