He developed along with William South. Burroughs and Brion Gysin the cut-up technique of writing poetry and literature. Beiles was involved with American beat poets Allen Ginsberg, Gregory Corso and Brion Gysin, and Burroughs at the legendary Beat Hotel in Paris. The photographer Harold Chapman recorded this period in his book The Beat Hotel (Gris Banal, 1984).
He co-authored Minutes to Go with Burroughs, Gysin and Corso (Two Cities Editions, 1960).
Beiles helped edit Burroughs" Naked Lunch. He worked with the Greek artist Takis and read his magnetic manifesto -- "I am a sculpture.
I would like to see all nuclear bombs on Earth turned into sculptures"—in 1962 in Paris at the Iris Clert Gallery. At this event he was famously suspended in mid-air by a magnetic field from a powerful magnet in a sculpture developed by Takis.
Beiles attributed his subsequent mental instability to this experience even though he insisted that Takis provide him with a helmet to protect his head from the magnetic field
Beiles wandered through Europe, including a spell in London and settled in the Greek islands during the 1970s. He fought frequent bouts of depression, mental illness and drug addiction. In later life he returned to South Africa and was associated with the Johannesburg-based Gallery III group of poets, writers, composers and performance artists and lived in the central and artistic district of Yeoville.
The poet had a burst of writing activity from 1991 to 2000, publishing a large number of poetry collections, including A South African Abroad (Lapis Press, 1991).
He died in relative poverty. A collection of writings about Sinclair Beiles called Who was Sinclair Beiles? was published by Dye Hard Press, Johannesburg, in 2009, co-edited by Gary Cummiskey and Eva Kowalska.