Alexandru Iacob became a member of the underground PCR in the early 1930s, but, after the Second Vienna Award assigned Northern Transylvania to Hungary, joined the KMP, becoming its Secretary for the region.
While in hiding, he recruited some new party members and followers, compensating for the wave of arrests carried out by the Hungarian Regency authorities among communist militants.
In 1947, he was moved to Bucharest, where he joined the staff of Vasile Luca, Minister of Finance, PCR Secretary and vice-Premier in the Petru Groza cabinet.
In 1948, soon after the establishment of a Romanian communist regime, Iacob became Deputy Minister of Finance and acted in that capacity until the spring of 1952, when he was arrested as part of the campaign against the so-called "right-wing deviation".
The defendants of the Luca trial—Luca, Iacob, Ivan Solymos and Dumitru Cernicica were officially rehabilitated in 1968, during the liberalization phase associated with the early years of the Nicolae Ceaușescu regime.