Born in Leeds, Jeffrey Harris started painting as a boy while exploring the Yorkshire Dales. He obtained a BA  at Leeds College of Art, majoring in painting, drawing and printmaking. An early influence on his work was visiting lecturer Victor Passmore. Following two years in the army, he completed a Bachelor of Education.

In 1956 Harris moved to Lelant, near St Ives, as the newly appointed art teacher of the secondary school in Hayle. He married Tasmanian-born painter Gwen LEITCH in 1959. The pair shared her studio (7 Porthmeor Studio) for the next 12 years, living in Academy Place and later on Bowling Green Terrace.

His early paintings were abstract and semi-figurative, usually in oil on masonite or canvas. He also made constructions and wooden reliefs. His painting often plays with flat two-dimensional perspective. Elements of pattern and abstraction, colour and symbolism referenced his childhood in Yorkshire and his father's work as a tailor. During 1967 Jeff lived at the Monastery St Elias in Devon, where he studied iconography. From 1966 to 1969 he taught painting and drawing at Falmouth Art School.

In 1970 Harris and his wife Gwen emigrated to Australia with their four children. After a spell in Tasmania, they moved to Adelaide. Throughout the 1970s and 1980s both Harris and Leitch taught at the South Australian School of Art, maintaining their art practice and exhibiting. Following his early retirement in 1990, Harris was able to focus exclusively on his art.

Gwen died in 2006. He remains an active painter in Australia. His 2022 retrospective at Belgrave St Ives reveals his considerable versatility, able to move fluently between representational and abstract pictorial modes. In his early work he responded to the Cornish landscape while traversing a modernist path through abstraction, while his later gestural canvases explore the geological forms of Australia.

In the UK, his work is held in collections such as the Arts Council, Southbank Centre, Cornwall County Council, Whitworth Art collection, Manchester University, Alston Hall, UK Education Department, Lancashire. It can also be found in private collections in the UK, Australia and USA.