In March 2016 the former monarch was diagnosed with cancer. He then underwent surgery and retired from public life. The Keeper of the crown was his eldest daughter Margareta. Mihai has five daughters, five grandchildren and three great-grandchildren and great-granddaughters, according to Lenta.ru.

In 1941 Romania entered the Second world war on the side of Nazi Germany. In 1944, when Soviet troops neared the Romanian border in the result of the Jassy-Kishinev operation, Mihai has teamed up with the anti-fascist opposition and declared war on Germany. Later, in 1945, Joseph Stalin awarded the monarch the order of "Victory". Michael I is one of the five foreigners, the holders of this highest Soviet military order.

In December 1947, the Romanian government has abolished the country's monarchy, and Mihai was forced to emigrate to Switzerland. Again to visit Romania, he could only in 1992, in 1997 he was returned to Romanian citizenship.