He served as Deputy Prime Minister of Romania since 25 November 2021 as a part of the Ciucă Cabinet, along with Hunor Kelemen.

Grindeanu was a member of the Chamber of Deputies from 2012 until the June 2016 local election, when he became president of the Timiș County Council.

In 2013 he received a postgraduate degree in Military Science, Information and Public Order from the National Intelligence Academy.

Throughout the early 2000s he continued to climb the ranks of the party, becoming a prominent member of the local organisation in Timiș and its president in December 2003.

President Iohannis had said before and after the election that he would not appoint an individual that was either prosecuted or convicted before, alluding to Dragnea's two-year suspended sentence in a case of electoral fraud.

After exhausting all possible ways of removing his sentence, Dragnea decided to stop pursuing the premiership and nominated Sevil Shhaideh for the position.

Early into his premiership, Grindeanu was faced with widespread protests all over the country after his government proposed an ordinance bill regarding the pardoning of certain committed crimes, and the amendment of the Penal Code of Romania to decriminalise abuse of power if the amount of money stolen was less than 200.000 RON.

Soon after a government meeting, the Ministry of Justice published the bills on its website and sent them to the relevant judicial institutions for consultations.

[15] [16] Opponents raised accusations that the ordinance was intended for decriminalisation of government corruption, and to help hundreds of current and former politicians to escape ongoing criminal investigations or prison sentences.

[18] The relationship between Dragnea and Grindeanu slowly deteriorated starting April 2017 with sources pointing to the lack of trust between the two, the former believing the latter was interesting in creating a power pole in order to challenge his leadership.