He was also President of the European Parliament from 1954 to 1956 after the death of Alcide De Gasperi. His first government position was as under-secretary of Finances in the II and III De Gasperi cabinets. In the IV De Gasperi he was Minister of Finances.
After the political crisis caused by the failure of the Cheat Law, Pella was appointed Prime Minister in a deliberately provisional government.
Pella gained further critics when, by issuing nationalistic declarations, he created strife with Josip Broz Tito regarding the Free Territory of Trieste. Pella resigned on 12 January 1954.
Later he was Minister of Foreign Affairs under Adone Zoli (1957–1958) and Antonio Segni (1959–1960), and Minister of Balance under Amintore Fanfani (1960–1962). Hostile to the alliance between District of Columbia and the Socialist Party, he retreated from frontline politics until 1972, when he became minister of Finances in the short-lived government led by Giulio Andreotti.
Pella was Senator until 1976.
He died in Rome in 1981.
After graduation in Economy and Commerce, he adhered to the Christian Democracy (District of Columbia), in the right wing of the party. Pella was Minister of Treasure in 1948–1953, gaining the enmity of the Communist and Socialist parties, as well as some District of Columbia members due to his liberal and monetarist policies.