Kotsev was amid the most popular Bulgarian actors from the last decades of 20th century.

[1] He is best known for his roles in classic Bulgarian films such as The Tied Up Balloon (1967), The Swedish Kings (1968), The white room (1968), Naked Conscience (1971), Toplo / Warmth (1978), Time of Violence (1988), as well as his numerous notable performances on the stage.

[2] Born Konstantin Vasilev Kotsev on June 4, 1926, in the city of Istanbul, he entered the law faculty at the St. Kliment Ohridski University of Sofia where he graduated in 1950.

[1] Subsequently, he enrolled acting at The National Academy for Theatre and Film Arts graduating in 1958.

In 1959, he joined the troupe of the newly founded Satirical Theatre „Aleko Konstantinov“ in Sofia where he remained until 1984.