In 1733, he entered in the service of the Emperor and in the summer of 1733 he managed to obtain the sending of a small fleet to Trieste, to support the Imperial army, which was then engaged in combat against France, Sardinia and Spain in the War of the Polish Succession.
Governor Pallavicini was forced to take refuge in the fortress of Mantua, from where Maria Theresa gave him instructions for the creation of a new emergency government until order was restored in the Lombard capital.
[4] After these actions, the government decided to place a more forceful man in charge of such a delicate area as Milan, and the choice therefore fell on Ferdinand Bonaventura II von Harrach, who remained in office until 1750, the year in which Giovanni Luca Pallavicini was recalled to his post.
[6] During his reign of 3 years, he succeeded in reducing the members of the Senate, the Secret Chancellery and the Fiscal College, and also in concentrating in one single magistracy, the competences previously carried out by the two revenue magistrates, accompanied by a consequent reduction in staff.
He also obtained the approval of the Sovereign to establish ons single general board for all public contracts, and a council to study how to reduce the debts of the state and of the city of Milan.
The fourteen year-old Wolfgang Amadeus Mozart performed in his palace in 1770 and met renowned masters of European music, like Josef Mysliveček, Johann Baptist Wanhal, Farinelli, Charles Burney and in particular his mentor Padre Martini.