This article examines Metcalfe’s major contributions concerning evolutionary theory, innovation and Schumpeterian dynamics, competition and innovation systems. Metcalfe's broad intellectual framework is first presented: the use of complementary approaches (theory, appreciative analysis, empirical work and case studies); the wide range of disciplines addressed (economics, technology, sociology, business studies and political science) and the successful combinations of a micro and a macro approach, of a supply- and a demand-side view and of focus on advanced economies and on developing ones. Then the article discusses Metcalfe's contributions regarding competition and selection within an evolutionary framework; innovation systems, institutions and entrepreneurship; and public policy in an evolutionary and system view.