[1] In the late 15th century, Macarius became a monk at the St. Paphnutius Monastery [ru] in Borovsk, where he would serve as a reader, subdeacon, deacon, and priest.
He was one of a few clerics who supported Vasili III's divorce from the barren Solomonia Saburova and blessed his second marriage with Elena Glinskaya.
He is also credited with beginning the Stepennaya Kniga ("Book of Royal Degrees") which traced Ivan the Terrible's lineage back to a fictitious brother of Caesar Augustus named Prus.
[4] Having secured the support of a powerful prince, Andrey Shuisky, Macarius was elected Metropolitan of Moscow and all Russia on 16 March 1542.
During Ivan IV's nonage and Shuiskys' regency, Macarius's relations with the Boyar Duma gradually worsened due to his constant "grief" over the disgrace of courtiers and church dignitaries.
During the synod of 1542, Macarius achieved the excommunication of Maximus the Greek's associate Isaac Sobaka, archmandrite of the Chudov Monastery.
Curiously enough, Macarius would later correspond with the exiled Maximus the Greek and include some of his essays in his the Great Menaion Reader, rejecting, however, his appeals for pardon.
During his Kazan campaign in 1559, Ivan the Terrible left Macarius in Moscow to "protect the tsardom", which made him a temporary head of state.
During the church councils in 1553–1555, Macarius supported the accusations of heresy, aimed at a boyar son Matvei Bashkin, starets Artemiy, and monk Feodosiy Kosoy.