He set up his first confectionery bakery in Milan in the 1920s, and opened his own pastry shop in 1925, where he directly sold his products.
In 1933, he expanded his business, with a pastry shop adjacent to Milan's Piazza del Duomo.
The shop became a popular spot in the prewar years, thanks to the production and sale of panettone, an Alemagna speciality.
Alemagna had the largest factory in Milan's Via Silva, with more than 30 baking ovens and 2,000 employees.
After World War II, Gioacchino retired and sold the company to his son Alberto.