Znamensky was born in a family of a priest and had four sisters and five brothers; one of them, Seraphim, became his long-term training partner and rival in athletics.

By the age of 20 Georgy was the fittest man in his locality, yet he later had two health-threatening accidents: once, during the harvest works, a horse stepped on his foot, which required a surgery.

In those years the brothers trained by running 16 km between their home and the factory where they worked, while their diet consisted of rye bread, potato, and plenty of milk (a bucket per day for two).

Contensting various 1000 m – 10,000 m events the brothers finished 18 times within the podium at the Soviet championships in 1934–1940 and set 24 national records.

At the onset of World War II in Russia they both volunteered as medical doctors to the Soviet Army.