Mario Dubsky was born to Christian parents, of Jewish extraction, who had recently arrived from Vienna as refugees from Nazism. He was educated at Burgess Hill school before attending the Slade School of Fine Art (1956-61). He was mentored by Dorothy Mead, a mature student who had studied with Bomberg and who passed on what Dubsky referred to as ‘Bombergian precepts’. Dubsky went to Rome in 1963 on an Abbey Major Scholarship which gave him the opportunity to travel widely around Europe. In 1969 he had his first solo exhibition at the Grovesnor Gallery.
On his travels around Europe, Dubsky came into contact with homosexual communities in Amsterdam and Berlin, after which he became open about his homosexuality. When in 1969 he travelled to New York on a Harkness Scholarship, he became involved in gay political activities. With John Button, he created a 40 foot long mural for the Firehouse, the Gay Activists Alliance Building in New York.
Dubsky taught at Wimbledon, Camberwell School of Art and the Royal College of Art. His work is well represented in a number of public and private collections including Tate and the Arts Council of Great Britain. He died of Aids in 1985 and was buried in Highgate Cemetery.