Throughout his long career as a painter, Sepp Scott exhibited at the Royal Academy and was a member of the Royal Watercolour Society. He was best known to the general public as a book illustrator and as the designer of posters for the London & North Eastern Railway and the London, Midland & Scottish Railway and many other companies. At the end of his career, Scott drew comics for the magazines Knockout, Sun and Thriller Comics Library. His paintings and watercolours were also used for the covers of these magazines. Partly because of this, they had great success and are today very popular among collectors.