Best known for his works on paper, Geissler’s paintings often depict scenes of woodlands, farms and harbours, almost always without figures. He joined the Royal Scots Regiment at the outbreak of World War I and was posted to northern France, serving in the Battle of the Somme. Following demobilisation from the army in 1919, he studied at Edinburgh College of Art where fellow students included William Gillies. In 1923, Geissler was awarded a travel scholarship from ECA and went to study in Paris with the cubist artist André Lhote. On returning from Paris, the influence of Lhote in Geissler's work softened as he developed his own style through close observation of the natural world. Geissler tutored at Edinburgh College of Art and Perth Academy in the 1920s, before taking up post in 1935 at Moray House College of Education, becoming Head of the Art Department in 1947 until his retirement in 1962. He was a member of the Society of Scottish Artists, of which he was President from 1954 to 1957, and of the Royal Scottish Society of Painters in Watercolour.