He will turn 80 on July 14.
He turned to neuroscience in 1982, when he was 49. However, his PhD student, Terry Sejnowski, got a degree in computational neuroscience few years earlier.
He himself came to NS community with "Hopfield networks" - in fact reinvented David Marr's "Collateral networks", described in 1971. However, JJH added a new venue to the old story: he wrote a "Hopfieldian". That was a function, which value does not increase along the network dynamic trajectories.
The numerous swarms of theoretical physicists immediately followed JJH in "neural network" research and he enjoyed his leading role for a while, but obviously, it became boring for him and he turned to real thinking about real brains. A notable for that first not "Hopfield network" Hopfield's work was notion of neural synchronicity. It's first significant result came exactly at the brink of the new millennium: a snobbish two-partite paper entitled "What is moment?" was published by him and his disciple C. Brody in Proceedings of National Academy of Sciences (December 2000/January 2001). It was interesting and even imposed a faint attempt to look for experimental verification of the Master's neural computational hypotheses [ ].