Konstantinos Stephanopoulos was born in Patras on 15 August 1926. He studied law at Athens University and practiced law from 1954 until 1974, as a member of the Bar Association of Patras. He first stood for election in 1958 with the National Radical Union (ERE) and was elected for the first time as Member of Parliament for Achaia in 1964. He was re-elected for the same constituency with the New Democracy Party in the elections of 1974, 1977, 1981, and 1985. From 1981 until 1985 he served as a parliamentary secretary and parliamentary spokesman for his party.
In 1974 he was Deputy Minister of Commerce in the National Unity government of Konstantinos Karamanlis. For the next seven years he served in a number of ministerial posts in the New Democracy governments: Minister of the Interior from November 1974 to September 1976, Minister of Social Services from September 1976 to November 1977, Minister for the Presidency from 1977 to 1981.
In August 1985 he withdrew from the New Democracy Party and on 6 September of the same year formed the Democratic Renewal Party (DIANA). He was elected Member of Parliament for Athens in the elections of 1989, while continuing as President of DIANA, until it disbanded in June 1994.
In the presidential election of 1995, after being nominated by the Political Spring Party (POLΑΝ) and supported by the ruling Panhellenic Socialist Movement (PASOK) he was elected President of the Republic on 8 March 1995. He became the fifth President since the restoration of a democratic system of government in 1974, winning the election on a third ballot with 181 votes.
Konstantinos Stephanopoulos succeeded Konstantinos Karamanlis as President on 10 March 1995. He was re-elected President of the Republic on 8 February 2000 on the first ballot after receiving 269 votes from the 298 MPs present, and remained in office until 2 March 2005.
He has received many honorary awards and the highest decorations of foreign countries. He is an honorary citizen of many municipalities in Greece.