He was deposed in 1866 by a broad coalition of the main political parties, after which parliament offered the throne to Prince Karl of Hohenzollern-Sigmaringen who subsequently became the new "Domnitor of Romania" (as Carol I).

Michael's first reign would be short lived at only three years, until his father Carol II came back to contest the title at the behest of a dissatisfied political faction that staged a sudden 'coup d'état' (in spite of the fact that only a few years earlier he had renounced in official documents, written and signed in front of his own father, all his future claims to the throne of Romania).

The kingdom of Romania was a constitutional monarchy for most of its existence with the exception of 1938–1944, during the dictatorships of Carol II (1938–1940) and Ion Antonescu (1940–1944).

[4] However, legally, Michael I could not exercise much authority besides some prerogatives such as being the Supreme Head of the Army and designating a plenipotentiary prime minister Conducător ("Leader").

[5] On 23 August 1944, with the Soviet Army already deep inside Romania's territory, Michael I deposed the German-allied dictator Ion Antonescu at the urging of the opposition parties and aligned the country with the Allies.

The young former king and former queen mother Elena were forced to leave Romania on January 3, 1948, in the royal train, at the request of the communist-dominated government.

The royal house is still popular[7] and in 2014 Prime Minister Victor Ponta promised a referendum on whether or not to reinstate the monarchy if he were re-elected.