Most of James Lester's work is landscape painting and figure painting. He works in watercolour, oils and pastel and his preferred method of working is to paint or draw from life, "en plein air", as this gives a freedom and directness to the painting. Botanical studies are an additional part of his work, as is portrait painting. He is a member of The Society of Botanical Artists and an Academician of the South West Academy of Fine and Applied Arts.

James has exhibited painting in the major exhibitions, including the Royal Society of British Artists, The Royal Institute of Painters in Watercolour, the New English Art Club, The City of London Exhibition, and The Royal Academy. His first solo exhibition was in 1970 and was held at the Tenterdon Art Centre in Kent.

A long standing interest in plants and the beauty of their structure led to commissions for botanical studies and election to the Society of Botanical Artists in 1986. Since then he has exhibited each year at the Society's Annual Exhibition in Westminster. Also he is co-author of an illustrated book on botanical painting: "Painting the Secret World of Nature", published by Search Press.

After moving to Devon in 1986, he continued to exhibit in the London galleries and then for ten years ran an art gallery in East Devon, which provided an outlet for much of his work and was the source of many commissions, including a number of prestigious portrait commissions. During this period he also ran a number of painting courses.

His work is in many private collections in the UK and in recent years has been included in exhibitions in Vienna, Sweden and Cardiff. In the South West his paintings have been selected for exhibition at the Royal West of England Academy in Bristol. In 2002 he had a solo exhibition of work at the Otterton Mill Centre Gallery and since the foundation of the South West Academy of Fine and Applied Arts in 2000, each year his work has been included in the Academy's Summer Exhibition.