In March 2009, following Prime Minister Ferenc Gyurcsány's announced resignation, Bajnai was nominated by the ruling Hungarian Socialist Party (MSZP) to become Hungary's next head of government.

[8] Many partners of Hajdú-Bét suffered serious losses during the time when the poultry market collapsed in 2003, Wallis group itself lost 10 billion forints (over 40 million Euros).

During his period as Minister, Hungary has won the right to host the European Institute of Innovation and Technology, and at the same time Mercedes has concluded a major FDI with the Hungarian Government in Kecskemét.

[12] In March 2009, Prime Minister Ferenc Gyurcsány resigned, announcing that he would hand over his position to a new premier with a higher support of the parties of the Hungarian Parliament.

Although Bajnai was reluctant to give in, after a week, with no tangible results in sight, and being asked by the majority of party stakeholders, who also assured him of their support of the needed austerity measures, he took the job.

In his first speech as PM, he promised drastic measures to stop the negative spiral of the Hungarian economy, and to ease the burden of the international crisis.

He had discussions with Jose Manuel Durao Barroso, President of the European Commission, and with Jaap de Hoop Scheffer, Secretary-General of NATO.

He made a two-day official visit to Israel, where he met Shimon Peres, Benjamin Netanyahu and the Opposition Leader, Tzipi Livni.

The Nabucco pipeline's intergovernmental agreement between Turkey, Romania, Bulgaria, Hungary and Austria was signed by five Prime Ministers (including Bajnai) on 13 July 2009 in Ankara.

The two premiers expressed regret over the circumstances of a failed visit by President László Sólyom to Komárno on 21 August and agreed to accept all recommendations of the Organization for Security and Co-operation in Europe high commissioner on national minorities.

Prime Ministers Gordon Bajnai of Hungary and Robert Fico of Slovakia signed a joint statement during their meeting in Szécsény.

Bajnai and Fico agreed to direct the attention of all political parties to the social risks of confrontation, and called upon the citizens of both countries to show tolerance and understanding.

They agreed to take resolute measures against extremist groups, and fight against all forms of xenophobia, intolerance, chauvinism, nationalism and violence, and the exportation thereof to one another's country.

[21] Between 20–24 September, Bajnai made an official visit to the USA, where he met President Barack Obama, the UN secretary-general Ban Ki-moon, he attended the Climate Conference of the UN.

Amongst others he had discussions with George Soros, Charles Gati, and major U.S. financiers and investors, he closed the day's trading at the New York Stock Exchange.

He attended talks with Prime Minister of the United Kingdom Gordon Brown and gave a public lecture at the London School of Economics and Political Science.

Between 18–19 October, he made a short official visit to Paris, where he met president of France Nicolas Sarkozy, PM François Fillon, and many French investors.

Hungary sent more troops to Afghanistan in line with then-current US strategy to enhance involvement there, Bajnai announced at a meeting with US Vice President Joe Biden in the White House on 4 December 2009.

The pledge been made in several steps during 2010: Hungarian troops mainly serve in logistics and training operations, on top of helping to secure elections in Afghanistan, Bajnai told journalists after the talks.

[23] At the beginning of 2010, Bajnai, as the Chairman of the Visegrád Four Grouping invited ten countries from the CEE region to sign a declaration for the support for stronger European energy policy cooperation and enhanced security of supply.

"),[29] when he proclaimed his support for such a "cooperation between hopeful left-wingers, disappointed rightwingers, politically abandoned free-thinkers and committed Greens" that his organization along with two other civilian body named Together 2014 (later simply known as "Together") as a reference to the date of the next general election in Hungary.

In order to facilitate the creation of this alliance, Bajnai voluntarily gave up his candidacy of Prime Ministership, in favor of Attila Mesterházy, the candidate of MSZP, the largest party of this coalition.

From September 2014, Gordon Bajnai returned to his original profession when he was named Group Chief Operating Officer of the Paris-based Meridiam infrastructure, a leading global investment fund.