Kovalev started boxing in 1994 at age 11, and made his amateur debut in 1997 in the Russian Boxing Junior Championship, where he won the gold medal in the middleweight juniors division.
Kovaljov startede boksning i 1994 i en alder af 11 år, og gjorde sin amatør debut i 1997 i det russiske Boxing Junior Championship, hvor han vandt guldmedalje i mellemvægt junior-klassen.