He was born in Athens on the 20th November 1920. His parents were Christos Kapnisis and Aphrodite Laoutari, a singer and actress in the popular music theatre of the time. Kostas Kapnisis himself always thought it an important incentive the fact that the well-known music house of the name Gaitanos with its huge piano dominating centre stage, was right across from his father shop. Following this, he will study the piano at the Greek Conservatory where he will have lessons with Skalkotas in 1943, and later with Vokos, Varvoglis, and Giannis Papaioannou.

In 1938 he composes his very first song ‘Gelas’ while still at school. At the age of 19 he will start composing professionally and it is then that he will make his debut in the theatre where he will be a protégé of the grand Lady of the theatre of those times Marika Kotopouli. He will collaborate with her on many occasions in the future.

At 21 he is hired at the then National Radio and Television Foundation (E.I.R.) as a musician and orchestrator. He will contribute decisively to the creation of the Light Music Orchestra.

In 1943 he will play the piano at the celebrated musical comedies of the Kotopouli theatre. There he will meet with his great friend and partner Alecos Sakellarios who commissions him to write the music for the play ‘I Lisa ta Ekane Thalassa’ in 1944. It is with this prolific playwright and script writer that he will collaborate again in ‘Fleur d’ amour’ in 1946. It is a production that featured the famous protagonists Myrat, Logothetidis, Konstantaras and the Kalouta sisters among others. 

He will follow the Kotopouli theatrical company’s tour in Cyprus and upon return in Athens he will write the score for Saroyan’s play ‘I Pio Krisimi Ora tis Zois sou’ where he will play the part of a colored pianist. The play stopped after a fortnight because of an accident of its protagonist Dinos Eliopoulos. Then Kostas Kapnisis will grab the chance to complete his military service. 

In the 50s he will be introduced to the cinema. In just a decade he will write music for 23 films, for some of which the sheet music will amount up to 200 pages.

Kapnisis’s important and lengthy career in the cinema starts with the film ‘Mia Nyhta ston Paradeiso’ where he shared the credits for the music with Thymios Papadopoulos. His first cinema works to stand out are ‘Haroumeno Ksekinima’ by Dinos Dimopoulos (1954), ‘To Koritsi me ta Paramythia’ (1956) and ‘To Matomeno Iliovasilemma’ (1959) by Andreas Labrinos where he wrote the music for the dancing scenes, sharing the rest of the score with Lykourgos Markeas. That same year this film will feature in the Cannes Film Festival. It is noteworthy that for the recordings he collaborated with the National Radio and Television Foundation (EIR) in whose orchestra he was the conductor and orchestrator. It was in EIR that he achieved writing epic music with influences from the Greek folk traditional music -of which he was a fan- but with a European streak, as he characteristically used to say. Up to 1959 he will continue to write songs, the majority of which will be sung by his peer Tony Maroudas.

In the golden decade of the sixties he will write the score for almost 60 films. It is a remarkable fact that in 1960 he will write the music for 4 films, the next year for 8 films, keeping the same request to have a big orchestra for the recordings at his disposal. In 1961 he will write the music for the film ‘Katiforos’ by Giannis Dalianidis for Finos Films. This film is considered to be a milestone for the Greek film industry. Doing the music score for this will be the beginning of his fruitful collaboration with Finos Films. He will work 17 times for them, establishing his name as a composer for cinema music.

Making use of contemporary music tendencies of the time such as jazz, cha cha cha, charleston and blues will enable him to pronounce a noir atmosphere in the films in the best way. It is in that period that Kapnisis will work together with numerous distinctive creators of the cinema, namely Alekos Sakellarios, Dinos Dimopoulos, Stavros Tsiolis, Panos Glikofridis, Vaggelis Georgiadis, Nikos Foskolos and Giorgos Tzavellas. 

In 1966 he will preside over the Panhellenic Music Association and he will diversify in plastic arts by using copper and exhibiting his work once. His permanent occupation will be on the radio from where he will be virtually expelled during the Dictatorship because of his democratic beliefs. His main work is the orchestration and conducting of the ERT orchestra, while he will form the ‘Kostas Kapnisis Band’ with a number of highly acclaimed musicians: Giannis Theodoridis (trumpet), Antonis Siveras (violin, trombone), Nikos Avgeris (violin), Nikos Gkinos (wind instruments), Spiros Alexandratos (trombone), Tasos Poulimenos (flute/saxophone), Marika (trumpet), Giannis Terezakis (organ), Aliki Krithari (harp), Andreas Rodousakis (contrabass), Nikos and Giorgos Lavranos (drums), Titos Kalliris (electric guitar) Giorgos Theodoridis (bass guitar) and Kimon Vasilas (organ).

He was awarded the prize for the best film music in the Thessaloniki Film Festival 4 times: in 1962 for the John Konte film ‘Ta Heria” which was not distributed in Greece, in 1969 for the film ‘Panic’ by Stavros Tsiolis. In 1977, the only year that the Festival is split in two, one organized by the government and one couner-festival, he will win the respective prize in both of them for the music in the documentary ‘Alexander the Great, between history and legend’. The composer will attend neither ceremony.

He also took part in many festivals overseas, in Spain in 1962, in Brazil in 1966 and in 1967, in Chile in 1974 and two times in Russia in 1963 and 1966. He was awarded the gold medal at the Song Contest in Brazil in 1967. 

Kostas Kapnisis was a permanent resident in Palaio Faliro, Athens. He passed away on the 4th July 2007.