He studied law at the National and Kapodistrian University of Athens and was awarded a Ph.D in Law in 1934. In 1937 he was appointed Associate Professor of Administrative Law at Athens University and in 1943 became a Professor at the Panteion University, where he served as rector from 1951 to 1958.

From 1951 to 1953, he was President of the Ellinikí Radiofonía Tileórasi. In 1952 he served as caretaker Minister to the Prime Minister's Office and Labour Minister in the Government of Dimitrios Kiousopoulos and in 1958 he was Minister for the Presidency in the Government of Konstantinos Georgakopoulos. In 1929, he was accepted into the Council of State, having come first in the entrance examination, and served as President of this body between 1966 and 1969.

In the Greek legislative election, 1974, Michael Stasinopoulos became a Member of Parliament in the nationwide ticket of the New Democracy Party. When a plebiscite (8 December 1974) established Greece as a Republic, Michael Stasinopoulos was elected as interim President of the Republic by a majority in the Hellenic Parliament. He served as Head of State from 18 December 1974 until 20 June 1975, that is, until the final shaping of the new regime by the revisionary assembly. Michael Stasinopoulos died on 31 October 2002.

Michael Stasinopoulos was a prolific writer. His literary work first appeared in the magazine "The Muse" (1920-1923). He published many scientific articles and literary works, as well as translations of French poetry and prose. In 1968 he was elected to the Athens Academy as a full member and in 1969 and 1970 he was put forward by the President of the French Council of State, René Cassin, as a candidate for the Nobel Peace Prize.