Lockyer, born the son of a surgeon-apothecary at Rugby in the English Midlands, started his career as a civil servant. He turned to astronomy and taught at the Royal College of Science, becoming director of the solar physics observatory and professor of astronomical physics from 1890 to 1901. He was one of the founders and the first editor of the British periodical Nature. He made many eclipse trips and played a leading role in attempts to reorganize the structure of British science. He wrote numerous books on popular science and virtually created the new discipline of astroarchaeology. Lockyer was knighted in 1897.

The spectroscopic work of Robert Bunsen and Gustav Kirchhoff so stimulated Lockyer that he moved from traditional astronomy to spectral studies. He worked mainly on the Sun, publishing The Chemistry of the Sun in 1887. He investigated sunspots and solar prominences discovering, with Pierre Janssen in 1868, that they could be observed spectroscopically in daylight without an eclipse. He also successfully identified the spectral line observed by Janssen in the 1868 eclipse as being an unknown element (found, he thought, only in the Sun), which he proposed to name helium (from the Greek for Sun: helios). His supposition about the existence of the element was confirmed in 1895 when William Ramsay isolated it from gases in the atmosphere. In 1873 Lockyer published his theory of dissociation to explain the appearance of further unfamiliar spectral lines. William Huggins had found a new bright line in the spectra of nebulae and thought it could be a new substance that he proposed to call ‘nebulium’. Lockyer argued instead that it could be an earthly element that had ‘dissociated’ into simpler substances under conditions of great heat and temperature, producing unrecognizable spectral lines. It was, however, difficult to make much sense of this view until the discovery of the electron some 20 years later and the correct explanation for the new spectral lines was not to be provided until the next century (by Ira Bowen).

In 1894 Lockyer published The Dawn of Astronomy, the first classic of what has since been called astroarchaeology, and in 1906 he produced Stonehenge and Other British Monuments Astronomically Considered. His aim in these works was to establish (without, of course, the benefit of computer and TV camera) that many ancient buildings were astronomically aligned. He did a good deal of field work, paying regular trips to Egypt and Greece as well as to the standing stones of Britain.

Not the least of his achievements was the creation of a new type of scientific periodical with Nature in 1869. It was by no means obvious that Nature would survive and it owes much to Lockyer's half century of editorship. The virtues of Nature were in fact the virtues of Lockyer himself – it relished controversy, was tolerant of a wide range of scientific views, and was quick to publish scientific results.