[2] During his time as Economy and Finance Minister, he worked closely with his Economic and Financial Affairs Council partners to prepare for the launch of the Euro in Greece.

Prior to this, Papantoniou worked at the OECD (1978–81), served as a Member of the European Parliament (MEP) from 1981 to 1984, and as advisor to the Greek prime minister on EEC Affairs and Integration.

Papantoniou has published numerous articles and books on topics related to economic and political developments in Greece, Europe and the wider world scene.

In November 2014, Papantoniou was convicted by an Athens court of failing to declare 1.2 million euros in a Swiss bank account held under his wife's name.

[2] On 24 October 2018, upon decision of the prosecuting authorities, Papantoniou and his wife were detained and sent to Korydallos prison, pending their trial for grave corruption and money-laundering charges, the losses for the Greek State being estimated at 400 million Euro.