Caccia Dominioni was born on 7 December 1913 in Milan, in Lombardy in northern Italy, to Ambrogio Caccia Dominioni, a lawyer, and Maria Paravicini; the family was a noble one, with origins in Novara, in Piemonte.
Caccia Dominioni graduated from the Politecnico di Milano in 1936, and opened a studio with two fellow-students, Livio and Pier Giacomo Castiglioni. He was in the Italian army during the Second World War, but when the puppet Republic of Salò was established in 1943, he refused to recognise it and fled to Switzerland. After the war he returned to Milan and, with Corrado Corradi Dell'Acqua and Ignazio Gardella, started Azucena, a company which designed both furniture and furnishings such as door-handles and lamps.
The multiple trajectories of postwar Italian architecture and design, particularly in Milan, would be inconceivable without Caccia. Present on almost every corner of his native city, Caccia's architecture subtly alters the urban texture. It is no exaggeration to say that Caccia's architecture is hidden in plain sight, and yet Caccia was never interested in "blending in." Close scrutiny reveals that he was especially skillful at making the pre-existing urban fabric seem to adjust to his interventions, rather than the other way around. And though one can plausibly argue that all important urban architecture participates in this kind of game, few in Milan have pulled it off with such a heady mixture of grace and aristocratic discretion as Caccia himself.