Michael was a younger brother of Nicholas II of Russia, Grand Duke Alexander Alexandrovich, Grand Duke George Alexandrovich and Grand Duchess Xenia Alexandrovna. He was also an elder brother of Grand Duchess Olga Alexandrovna.
Nicholas II later legitimated George, who took the style "Count Brasov", although he never obtained any rights to the throne. Brasov died in a car crash at age 21 on July 22, 1931. On July 28, 1935, Countess Brasova was granted the title-in-exile of HSH Princess Romanovskaya-Brasova by her late husband's cousin Grand Duke Cyril Vladimirovich, pretender to the Russian throne.
Upon the outbreak of World War I, Mikhail Alexandrovich requested the Tsar's permission to return to Russia and to the Army, with the understanding that his wife and son would come too. He returned home as a Russian general, leading the Savage Division, formed of Chechens and Daghestani troops.
His paternal grandfather was assassinated by Ignacy Hryniewiecki of the Narodnaya Volya on March 13, 1881. His father succeeded him as Emperor. Nicholas became heir apparent while George was second-in-line to the throne, and Michael Alexandrovich was third. When their father died on November 1, 1894, his oldest brother became Nicholas II, while George Alexandrovich became heir presumptive, and Michael stood second-in-line to the throne.
George suffered from poor health and died of tuberculosis on August 9, 1899. Michael became heir presumptive to his still-reigning elder brother Nicholas II, expected to become Emperor in his own right since Nicholas and his Empress Consort Alexandra had several daughters, but no son. Under Russian law, the eldest daughter, Grand Duchess Olga Nikolaevna, could only succeed to the throne if all male Romanovs, no matter how distantly related to the Emperor, pre-deceased her.
Michael continued as heir presumptive until August 12, 1904, when the birth of Tsesarevich Alexei Nikolaevich to Nicholas II and Alexandra resulted in the newborn becoming heir apparent to his father. Michael again became second-in-line to the throne.
We bequeath Our inheritance to Our brother the Grand Duke Mikhail Alexandrovich and give him Our Blessing on his accession to the throne.The abdication was countersigned by the Minister for the Imperial Court, Count Freedericksz. According to Russia's Fundamental Laws, Michael became Emperor on the day the abdication of his predecessor was lawfully promulgated. Michael was, in fact, proclaimed as "Emperor Michael II" to Russian troops and in some cities, though not in most.
Michael's accession was accepted by the newly-formed Provisional Government, with the exception of the representative of the newly-formed Petrograd Soviet, Alexander Kerensky. He anticipated rejection of the monarchy's continuance by the Soviet's members, and, along with most other leaders of the Provisional Government who met with Michael the next morning, Kerensky sought to dissuade Michael from attempting to reign. He and two lawyers (including Vladimir Nabokov, father of the future writer) drafted a declaration of conditional acceptance for Michael to sign, which he duly did the following day, on March 16, 1917. In it, Michael neither abdicated nor refused acceptance of the throne, but deferred exercise of the Crown's authority, conferring the Tsarist imprimatur upon the Provisional Government's regime until, and for the purpose of, democratically ascertaining whether the Russian people wished to retain or replace the monarchy. The manifesto stated, in part:
I am firmly resolved to assume supreme power only if such is the will of our great people, who must now by universal suffrage and through their representatives in the Constituent Assembly establish a form of government and new fundamental laws of the Russian State.
Michael's diary entry of 15 March 1917 (mentioned in Before the Revolution — A view of Russia under the last Tsar by Kyril Fitzlyon {Allan Lane Publication 1977, 256 pages, ISBN 0713908947}) is noteworthy, though it did not prove prescience:
Any hopes that Michael might be able to assume the throne, following the election of the Constituent Assembly, were overtaken by events. His renunciation of the throne, though conditional, marked the end of the Tsarist regime in Russia. Given that he never ruled, and reigned for at most a few hours, his brother Nicholas II is regarded as the last actual, or de facto Emperor, while Michael's "reign" is relegated to a largely forgotten footnote of history.
On 1 September 1917 Russia was declared republic by the Provisional Government, which move was heavily criticized both from left wing (as an attempt to bypass the Constituent Assembly) and right wing forces.