He has held important positions with the Intesa Sanpaolo Banking Group, where he worked from 1981 to 2013, taking over the management of Banco di Napoli, Banca dei Territori Division and covering the position of General Manager of the Intesa Sanpaolo Group. From 2003 to 2013 he was Board Member in several banks and other financial intermediaries. After resignation from Intesa Sanpaolo Group in June 2013, Giuseppe Castagna was appointed as chairman of Italian Private Debt Initiative of Muzinich & Co. From 2014 to December 2016 he was General Manager and CEO at Banca Popolare di Milano and since January 2017 he has been CEO of the new Group Banco BPM. In 2020, he is awarded the title of Cavaliere del Lavoro by the President of the Italian Republic, Sergio Mattarella.