Григорей was born in 1742 in Фоминское с. Григорей's father was Осип Иванович Фомин and his mother was Анна Сергеевна-Фомина. His paternal grandparents are Иван Фомин and <Unknown>. He had two brothers and a sister, named Андрей, Пётр and Гликерия. He was the second youngest of the four children. He died at the age of 28 in 1770.