John Sweeney was born in Tangier, Morocco, and relocated to the UK with his family in 1965. He completed a foundation course at Walsall Art College, subsequently studying painting and drawing at Epsom School of Art and Design (1979-1982) under Peter Peterson.

From the late 1970s onwards, Sweeney's work has been successfully shown at the New English Art Club, The Royal Society of British Artists, and the Royal Academy summer exhibitions. He has also exhibited with the Birmingham Society of Artists and held solo shows with the Neville Galleries in Canterbury.

He is a former member of the East Croydon Art Society, and Reigate Society of Artists, and is currently a member of the East Kent Society of Artists. He is also a member of a St Ives/Cornwall-based group, 'the figurative and representational artist group'.

Since 2017 he has been exhibiting with STISA, and was elected to membership in 2020, when he moved permanently to Cornwall. His work has sold not only in the UK, but also in the USA and Hong Kong.