He was the sixth metropolitan in Moscow to be appointed without the approval of the Ecumenical Patriarch of Constantinople as had been the norm.

In 1495, he was elected Metropolitan of Moscow after the removal of Zosimus on charges of heresy and sodomy.

In 1501, Simon wrote a letter to the clergy of Perm, asking them to admonish their flock, knyaz, and ruling elite to eradicate idolatry and pagan beliefs among ordinary people.

[1] Despite this, the Sobor of 1504 condemned the Heresy of the Judaizers, which repudiated some of the dogmas and rites of the Russian Orthodox Church, thus confirming Gennady's major activity during his archiepiscopate.

The same sobor also dealt with the issue of debauchery among the widowed clergymen and deacons.