John Hertz received his PhD from the University of Pennsylvania in 1970. After a postdoc at the Cavendish Laboratory, University of Cambridge, he joined the faculty of the James Franck Institute, University of Chicago as an Assistant Professor. He became Professor at Nordita in Copenhagen in 1980. Since 2007 he has also been Professor at the Niels Bohr Institute and divides his time between Copenhagen and Stockholm.

In the beginning of his career, John worked in condensed matter theory, particularly on magnetism in systems with highly correlated electrons and on phase transitions, which led to his well-known work on quantum critical phenomena. He then turned to the statistical mechanics of disordered systems, particularly spin glasses. This, in turn, led him to develop an interest in neural networks. With Anders Krogh and Richard Palmer, he wrote what is still the standard book on artificial networks. In recent years his focus has been on biological networks, particularly in modeling the dynamics of neural networks in the neocortex. His current work deals with the inverse problem for networks: Given records of the spiking history of many neurons, how can one infer their connectivity (and other features of the network)? Spin glass theory turns out to be useful in this problem, both as the source of an effective algorithm and for understanding the statistical properties of the network.

His collaborative activity in the Nordic region includes organizing two Nordic networks on neural computation, teaching and collaboration with groups in Norway and Sweden, numerous summer schools and conferences, and supervision of MS and PhD students.