President of the PC

In 2006, Daniel Constantin joined the Conservative Party (PC), where he coordinated the work of the European Funds Department. In 2010, following an extraordinary congress of the party, he was elected president of the PC, with the support of the party's founder, Dan Voiculescu. At the age of 32, Daniel Constantin became the youngest party president in Romania. He stayed in that office until the dissolution of PC in 2015.

Minister of Agriculture

In 2012, Daniel Constantin was appointed the Minister of Agriculture in the Victor Ponta cabinet.^[1] The agriculture portfolio and the appointment of Constantin to this post were announced by the Prime Minister Ponta before the presentation of the composition of the government, which showed that his position was established before the negotiations of the other portfolios.

Daniel Constantin has a personal debt of almost 300,000 euros to Dan Voiculescu. The Ministry of Agriculture, under the leadership of Daniel Constantin, is in dispute with the Grivco group, controlled by Voiculescu, accusing him of a damage of 60 million euros, following the fraudulent privatization of the Food Research Institute (ICA). Voiculescu was sued in December 2008, in the case regarding the privatization of ICA, a state-owned company acquired by Voiculescu from the state after it was undervalued by over 60 million euros. Thus, Constantine is suspected of having been appointed minister only to remove them.^[2] Subsequently, by virtue of this debt, the National Agency for Fiscal Administration won in 2018 a lawsuit against Daniel Constantin in which the state must recover part of the damage from the ICA file from the payment of that debt.^[3]

On 9 December 2012, he won the became MP from Argeș County.

ALDE co-chairman

Through the merger of the Conservative Party and the Liberal Reformist Party (PLR), the Alliance of Liberals and Democrats (ALDE) party was founded on 19 June 2015, with Daniel Constantin as its founding member. Together with former PLR president Călin Popescu-Tăriceanu he co-chaired the party, that joined a coalition with the Social Democratic Party (PSD) under Liviu Dragnea after the 2016 parliamentary election. In the cabinet of Sorin Grindeanu, Constantin served as deputy prime minister and minister of environment and climate change from January to April 2017.

PRO Romania and PNL

In May 2017, Daniel Constantin and former education minister Sorin Cîmpeanu left ALDE after a conflict with co-chair Popescu-Tăriceanu. Together with former Prime Ministers Victor Ponta who had been expelled from PSD, they founded the social-liberal Pro Romania Party (PRO).^[4] The new party was led by Daniel Constantin as interim chairman, until Ponta took that position at the first party congress in October 2018. In November 2019, Constantin and six other PRO deputies voted, against Ponta's order, for the new government of Ludovic Orban of the National Liberal Party (PNL). In early 2020, Constantin alongside Cîmpeanu and three other former PRO lawmakers joined the PNL.^[5]