In addition to this, Castiglioni taught as a professor at the Faculty of Architecture in Turin and at the Polytechnic University in Milan, where he had even previously been a student. Castiglioni was very industrially oriented and was inspired by everyday things, often using simple, everyday materials. He sought to use as many materials as possible to create maximum impact through the use of forms. During his lifetime he designed over 150 products and many of his most famous furniture designs and lamps are still being produced today.

Achille Castiglioni was very industrially oriented and was greatly inspired by everyday objects. He often used simple and common materials and tried to use as many materials as possible to create forms with maximum effect. His designs can be summed up as a mix of simplicity, irony and joy, as well as his interest in the manufacturing process and new materials.

Simple everyday objects became sophisticated design solutions through Castiglioni’s designs. Livio dropped out of the collaboration early on, and after the death of his other brother Giacomo in 1968, Achille continued on his own. Achille Castiglioni has won countless design awards, including the prestigious Compasso d’Oro nine times. In 1997, the Museum of Modern Art in New York organised an exhibition of Castiglioni’s earliest works. The museum also has some of his most important works in its permanent collection. Achille Castiglioni worked extensively with brands such as Flos, Zanotta and DePadova. His most famous works include the Snoopy, Arco, Fucsia and Taccia lamps and the Mezzadro and Sella stools. Several of Castiglioni's world-class early works can be found at the Nordic Gallery.