He started his artistic career as a musician influenced by Erik Satie and an author of dadaist poems.
He was a publisher of the books Œesophage and Mariewith his lifetime friend and soulmate René Magritte.
There he became the director of the London Gallery (which he ran during the late 1930s and after the war with Roland Penrose) and the chief editor of the London Bulletin (1938–1940), which was one of the most important bulletins among the English-language Surrealist periodicals.
[1] Mesens died in 1971 following a "long, lingering, painful illness".
[2] According to an obituary published by poet and historian Franklin Rosemont, Mesens committed "suicide by absinthe", drinking himself to death by wilfully disregarding doctors' orders to abstain from alcohol.