Dover began playing the saxophone and clarinet as an autodidact. At the age of 15 he founded his first jazz band and in 1948 won an award for best clarinettist at the International Jazz Competition of the Belgian Hot Club. From 1955 he worked as a professional musician in the orchestras of Ernst van’t Hoff, Léo Souris, Jeannot Morales, Jack Say and Henri Seghers. During these years he played among others. with Don Byas, Johnny Griffin, Slide Hampton, Bill Coleman and Horace Parlan. In 1963 he founded a jazz octet with which the album St. Tropez Jazz 0ctet goes Swing was created for the Europa label, stylistically based on the Kenny Clarke / Francy Boland Big Band. From 1966 he led a big band and played ten years in the orchestra
In addition to jazz, Dover also worked in the field of pop music, accompanied Caterina Valente on a world tour and played with artists such as Stan Getz, Shirley Bassey, Aretha Franklin, Natalie Cole, Barry White and Julio Iglesias. In the early 1970s he played in the fusion band Placebo, founded by Marc Moulin, of which Philip Catherine also belonged for a time. In 1975 he founded the Sax Combination formation, a saxophone quintet.
The St Tropez Jazz Octett is an alias for The Johnny Dover Octet and features Marc Moulin.