Keith Henderson studied at the Slade School of Art and the Académie de la Grande Chaumière in Paris. He served in both the First and Second World Wars, working as an official war artist in the latter. He kept diaries throughout his service, often recounting the difficulties of practising his art in a military setting:
May 6, 1940 - "Today I tried the experiment of taking up more than mere notebooks. I took a canvas, a dozen brushes and a full set palette. The Palette was disastrous [...] I remembered noticing an air gunner holding the palette at a dangerously acute angle as he handed it to someone. And worse. Nearly all the so carefully arranged large clumps of paint round the palette’s edge were, I saw now with dismay, gone. They had evidently slipped off or been smeared off. But I could not be without them. They must be found, scraped up penuriously from the floor or anywhere. Then I saw the legs of the air gunner. My precious cadmium red! The observer, the pilot even, all were strangely daubed handed round proved in that cramped space more distributive than cleansing. Their hands, their faces, their flying kit were crimson, blue, white, black, yellow, or tartan. It was a great success."