Born in Manchester John Hopkinson became a student at Owens College, Manchester where he studied mathematics. He won a scholarship to Trinity College, Cambridge in 1867 where continued to study mathematics. While there he was awarded a Whitworth Scholarship and went on to study for a science degree at the University of London.

He chose to become an engineer, rather than an academic and in 1871 he went to work for his father, who was also a mechanical engineer, before becoming manager and engineer at Chance Brothers, Birmingham. He worked in the lighthouse and optical department during which he developed a system of varying the length of flashes for various lighthouses for sailors to be able to recognise individual lighthouses.

He spent the rest of his life working on various aspects of electricity and published several academic papers. He left Chance Brothers and set up as a consulting engineer and was elected to the Royal Society in 1878. He worked on the theory behind the why the dynamo worked as well as patenting a three--wire distribution system. In 1890 he was appointed professor of electrical engineering and head of the Siemens laboratory at King’s college, London to conduct further research on dynamos.

By 1891 he was appointed by Manchester corporation to advise on an electricity lighting system for the city. During this period, he was also working on several other projects for various corporations installing new electric tram systems. As a consulting engineer on several tramway systems he became a member of the Institution of Civil Engineers in 1877. He also became a member of the Institution of Electrical Engineers and was their President between 1890 and 1896.

Sadly, his career was cut short as a result of an alpine accident in Switzerland in 1898, where he a three of his children were killed.