Born on 8 May 1885 in Camberley, Surrey, his father was Charles Rudyerd Simpson, a Major General, and his mother, Leonora (nee Devas). Initially the artist was educated by a private tutor, and later (1904) attended the Herkomer School at Bushey. In 1910 he was in Paris studying at the Academie Julian.

Simpson's first visit to St Ives was in 1905. He married Ruth ALISON in 1913 and together they led a busy life of teaching, painting and writing, for some years running the St Ives School of Painting. 

Walter (as he was known) and Ruth were to live a peripatetic life, living at Polwyn House, Newlyn from 1913 to 1914 (where their daughter Leonora was born), Carbis Bay (1914-16), Lamorna (1916-18), St Ives (1918-24), London (1924-1931), and Lamorna again (1931-45).

The outbreak of World War II resulted in a period of financial hardship as commissions and sales dried up. He became a deputy chief warden in Air Raid Precautions and an auxiliary coastguard but it was a difficult time and so they left Lamorna, moving to Dorset where Walter had a job as a farm labourer. On their return to Lamorna in 1943, he joined STISA and resumed exhibiting, to critical acclaim.

In 1946 they settled in Penzance. Ruth died in Redruth in 1964. 

Simpson's published and unpublished writings, family papers, letters and diaries are in the WCAA Collection, as bequeathed by their late daughter, Leonora Simpson. A full biography of the artist by John BRANFIELD was published in September 2005 by Sansom & Co, to coincide with a major retrospective exhibition at Penlee House.

Walter's own books include: Trencher and Kennel; Emily Bronte; El Rodeo; Composition for Photographers; Animal and Bird Painting; and The Fields of Home for which he provided both the text and the illustrations.

His illustrated works include: The Fellowship of the Horse by S H Goldschmidt; Practical Jumping by J L M Barrett; Old Montreal with pen and pencil; Horseplay for Boys & Girls by John Thorburn; Manners and Mannerisms, A book for fox hunters by Crascredo (Country Life); Son of a Gun by Major Kenneth Dawson; The Gone Away by Dorothy Una Ratcliffe; Wit and Wisdom of the Shires by Major Guy Paget; Unknown Cornwall (numerous colour plates, monochrome and textual vignettes) by C E VULLIAMY; A Pastorale, with foreword & poem by Lady Jane Butler (12 woodcuts); Leicestershire and its Hunts (London: John Lane, Bodley Head 1926); The Harborough Hunt Country (London: John Lane, Bodley Head 1926).

In 2005, the WCAA published a previously unknown manuscript written and illustrated by Charles Simpson, entitled The Country of the Woodlanders, A Wartime Memoir of Hardy's Wessex. This book is available at Penlee House, Penzance, and by order from our On-line Bookroom.