Since 1595 he was Archbishop of Polotsk (originally Orthodox) and in 1596 accepted the Union of Brest, became Greek Catholic.
Zahorskyj was named as coadjutor on May 5, 1595, for the Archeparchy of Polotsk.
On September 22, 1595, the Polish king Sigismund III Vasa named him archbishopric of Polotsk.
In 1594 - 1595, Hermann Zahorskyj signed Uniate documents as "nominated" to the archbishop of Polotsk.
[1] On 19 October 1596 he was one of those Orthodox hierarchs who supported and signed the act of the Union of Brest,[2] formally became a Greek Catholic bishop till his death in 1600 or 1601.