Greece profile - Leaders
President: Prokopis Pavlopoulos
Born in 1929, Prokopis Pavlopoulos, a veteran politician of the centre-right New Democracy Party was elected president by parliament in February 2015.
The vote was the fourth attempt to elect a successor to Karolos Papoulias, of the Pan-Hellenic Socialist Movement (Pasok), after previous failures triggered the downfall of the government of Prime Minister Antonis Samaras and snap parliamentary elections.
The presidency is a largely ceremonial post, as executive power resides with the prime minister.
Prime Minister: Alexis Tsipras
Alexis Tsipras swept into power by winning snap elections in January 2015 on promises to ease the tough austerity imposed on Greece as part of international bailouts.
His leftwing Syriza party only narrowly missed out on winning an absolute majority in parliament, and formed an anti-austerity coalition with the nationalist Independent Greeks party.
He vowed to renegotiate bailouts worth €240bn (£179bn; $268bn) granted by the European Union, European Central Bank, and International Monetary Fund to keep heavily indebted Greece afloat in return for painful government spending cuts and restructuring.
Mr Tsipras and his allies argued that austerity had devastated the Greek economy, making it even harder to reduce the debt.
Soon after coming to power, his government announced a series of measures to reverse austerity, including raising the minimum wage and rehiring public sector workers, prompting fears of a Greek debt default and a resulting exit from the euro.
Voters rejected the eurozone creditors' bailout terms in a July referendum, only for Mr Tsipras to endorse even tougher terms for a third bailout agreed the following month.
Born in 1974 - the year Greece returned to democracy after a brutal seven-year military dictatorship - Mr Tsipras joined the youth organisation of the Greek Communist Party while at university.
He went on carve out a political career in the broader radical left Synaspismos movement, and was elected its leader in 2006.
In 2010, the economic crisis transformed Syriza - a left alliance formed around Synaspismos - into the main voice of those opposed to the conditions attached to international bailouts, and it came second to the centre-right New Democracy party in elections 2012.
Mr Tsipras is known for wearing his shirts open-necked but once joked he would put on a tie on when Greece gets a debt write-off.
His predecessor, New Democracy leader Antonis Samaras, in 2012 formed a coalition committed to pushing through the EU-IMF austerity measures, despite substantial public opposition.
His government to a certain extent succeeded in stabilising Greece's severe fiscal crisis, but came unstuck in the dying days of 2014, when parliament's failure to elect a president triggered an early election.