Boșcodeală was later convicted in 2015 for abuse of office during the period 2002–2008, by diverting public funds to a football team and other private companies of which he was a shareholder.

He ran against Senator Vasile Ion, who eventually withdrew from the race, accusing Ciolacu of rigging the internal elections.

[35] Tudose's predecessor, Sorin Grindeanu was ousted[36] from his position by a vote of no-confidence initiated by PSD itself, then under the leadership of Liviu Dragnea.

Since the procedure of calling early elections laid down in the Constitution of Romania is complicated and difficult to trigger, and seeing PSD still had the necessary majority to form another government, the president decided to name Mihai Tudose, Dragnea's newest proposal as ,prime minister.

Tudose was not, however, Dragnea's first choice and, the PSD leader needed to find ways to control him better than Grindeanu, who had shown him that the office of prime minister was strong enough to allow its holder to wrestle his power in the party away from him.

For this reason, Ciolacu was named deputy prime minister in the Tudose Cabinet, in order to become Dragnea's ears in the government.

In January 2018, Tudose attempted to take full control of his government by asking the resignation of his Interior Minister, Carmen Dan,[38] a Dragnea mouthpiece and loyal lieutenant.

As it became quite apparent that this was another power struggle between the prime minister and the leader of the PSD, Ciolacu publicly positioned himself in the Tudose camp.

Seeing that a majority of the party remained loyal to Dragnea, Tudose decided to resign[39] to evade a motion of no confidence like his predecessor.

[43] However, his election was won only narrowly and with the support of the PSD-breakaway party, PRO Romania, and its member, former Prime Minister Mihai Tudose.

He supported Viorica Dăncilă's bid to the presidency of Romania but after her defeat and her historically weak result, Ciolacu went on to take control of the party.

In early March, they announced plans to move the Congress online in light of the epidemic-related ban of gatherings of more than 1000 people.

[47] Ultimately, the Congress took place on 22 August 2020 and resulted in Ciolacu's election as leader of PSD, defeating Eugen Teodorovici on an overwhelming 1310–91 margin.

[10] Marcel Ciolacu assumed the office of Prime Minister of Romania on 15 June, in accordance with an informal rotational government agreement with the National Liberal Party in 2023.

[48] On 2 September 2024 the Ciolacu cabinet approved a legislative proposal to transfer one of Romania’s air defense systems to Ukraine following a series of aerial attacks by Russian forces.

Ciolacu was accused of conflict of interest causing damages to the municipality by inflating the Mecan contract by approximately 1.3 million euros.

[69] Since the beginning of the relationship between Ciolacu and Docuz, the latter's sister, Elena Arghir, became a member of the Council of Administration of the Romanian Lottery, at the request of the PSD.

[69] Former PSD Finance Minister Eugen Teodorovici declared for the Romanian press in February 2024 that Docuz and Ciolacu have a child.