He held positions at the Bucharest Chamber of Commerce (which backed his election as an independent senator in 1933) and Banca Commerciale Italiana (from 1942), and headed Creditul Românesc.

[1] Named interior minister in the second Constantin Sănătescu cabinet, he fought against the imposition of communism and the transformation of Romania into a Soviet satellite, earning him sharp attacks from the Romanian Communist Party.

His subordinates at the ministry included Teohari Georgescu, undersecretary for administration, and General Virgil Stănescu who, with Dimitrie Nistor, was in charge of the Siguranța secret police.

The day after the cabinet took office, dissent began to surface among the participating parties, against a backdrop of Soviet occupation and the Romanian Army fighting in World War II to the west.

[4] The government's repressive measures in response to popular demands hampered its ability to act, so that prefects and mayors were soon installed without ministry authorization in Arad, Brăila, Brașov, Târgoviște, Hunedoara, Ploiești, Timișoara and Lugoj, with nearly all office holders replaced by the end of November.

Domestically, the security situation was uncertain, with agents working for the ministry informing on those being watched when they joined political parties, as well as on the disorder caused by the Soviet occupiers.

In August 1946, he was seriously wounded in an assassination attempt at the Pitești tribunal that left two dead and sixteen injured, and Soviet pressures for the PNȚ and other historic parties to be dissolved were growing.

[6] Under pressure, he made statements partly disassociating himself from Maniu, calling him a "gloved dictator", and this collaboration allowed his wife, Fulvia, to be freed sooner,[2] after three months of detention.

The agent asked Penescu to launch a campaign underlining the historic basis for Romania's claim to Transylvania and the purported risk of Hungary retaking the province.

[11] Under continued surveillance from Romania, he kept up his campaigns, for instance going to Madrid for the 1980 CSCE conference and handing delegates a document detailing his country's internal situation.

[8][13][14] Nicolae Pleșiță, a general in the Securitate, was linked to the bomb; another one was sent the same day to the dissident writer Paul Goma, who called the police instead of opening it.