Henry George Lyons was born in London on 11 October 1864. He was educated at Wellington College (1878–82), where he was a scholar and showed early interest in geology; he was elected to the Geological Society at the age of eighteen. From the Royal Military Academy, Woolwich he progressed as lieutenant, Royal Engineers, to Chatham for a course of military engineering. In 1890 Lyons was posted to a company of the Royal Engineers at Cairo where he found time for research in geology and Egyptology. His reputation among engineers and archaeologists was established in 1895 following his report to the public works ministry ‘The Island and Temples of Philae’; the temples on Philae were due to be submerged for most of the year upon the completion of the Aswan Dam. On 6 July 1896 Lyons he married Helen Hardwick. They had one son and one daughter.

In 1898 it was recommended that Lyons head the cadastral (revenue) survey of Egypt. Lyons retired from the army and from 1901 took permanent service under the Egyptian government to build up a joint geological and cadastral survey department. His geological survey also covered aspects of geodesy, meteorology, and hydrology, and he published the respected Physiography of the River Nile (Cairo, 1906), which incorporated much original research. By 1908 he had also begun an observatory and a meteorological office and appears to have been the first to explore the upper atmosphere by use of instrument-carrying kites.

In 1911 Lyons was appointed secretary to the advisory council and assistant to the director of the Science Museum. When war broke out, he was recalled to organize recruiting for the Royal Engineers, and later to create a special meteorological service for the Royal Engineers. He then became successively administrator and director of the Meteorological Office. In 1919 however he returned to the Science Museum, becoming director in 1920. Attendance figures almost tripled during his directorship. He was knighted in 1926 and he retired in 1933.

Recognition also came to Lyons from the wider scientific community: he was elected a Fellow of the Royal Society in 1906, where he later held the roles of foreign secretary and treasurer; became secretary-general of the International Union of Geodesy and Geophysics in 1919 and became general secretary of the International Research Council, later the International Council of Scientific Unions in 1928. He received the Victoria medal of the Royal Geographical Society (1911), the Symons gold medal of the Royal Meteorological Society (1922), and the honorary degrees of DSc (Oxford, 1906) and ScD (Dublin, 1908). Lyons died at his home in Great Missenden, Buckinghamshire on 10 August 1944.