His father, Nikolay Kruglov, was also a biathlete.

Kruglov Jr. has won a couple of medals with the Russian relay team.

He is a two-time World Champion in the men's relay and a two-time World Champion in mixed relay.

Also he won silver medals at the 2005 World Championships and the 2006 Olympics.

[1] All results are sourced from the International Biathlon Union.