He was a three-time World Champion, winning the bantamweight title consecutively from 1973 to 1975.

Kirov won four European titles, winning the bantamweight class in 1969 and 1973–75.

Kirov was responsible for starting the long-line of great Bulgarian lifters, especially in the lighter classes.

He began competing in 1962 at the Chernomorets Club with coach Ilya Babachev, later transferred to Neftochimic Burgas.

Only a 156 cm tall competitor, fitting perfectly into the bantam scales, he dominated the home scene for a decade.