Sources of difficulty in insight problem-solving have been identified, but current theories are less successful at explaining discovery of solution ideas. Here, we explore the role of expertise in promoting insight. In Experiment 1, experienced designers and financiers solved visual and verbal problems. Expertise did not influence solution rates for verbal problems, but designers solved more visual problems than financiers, despite similar incorrect initial attempts. In Experiment 2, experienced and novice designers attempted problems either unconstrained, prevented from drawing, or sitting (...) on their hands to prevent drawing and gesture. Hand and drawing constraints removed the positive benefits of expertise. Experienced designers appear to solve visual problems by using strategies to explore the visuo-spatial environment in search of new representations. The results indicate that expert strategic knowledge can be a source of insight. They also show that strategic transfer of expertise to far domains can be achieved. (shrink)