Harold B. Dixon was educated at Christ Church, a college of the University of Oxford, obtaining a BA degree with first class honours in natural science in 1875. Subsequently he was awarded the degree Master of Arts (1878), and years later the degrees Doctor of Science and Doctor of Philosophy. He lectured at Trinity College, Oxford, from 1879 to 1886, and also at Balliol College from 1881 to 1886. In the latter year he was elected a Fellow of the Royal Society of London, while at some time he was also elected a Fellow of the Chemical Society. Also in 1886 he accepted an appointment to lecture at Owens College, Victoria University of Manchester, where he became professor of chemistry in 1891. His research related mainly to the study of explosions in gases and its application in the mining industry, a topic on which he published some 50 papers between 1880 and his death in 1930. For example, he found that a dry mixture of gases is less likely to explode than a moist mixture, but that the explosive wave travels faster in a dry mixture. He also showed that carbon monoxide reduces steam at high temperatures. He served on the Royal Commission on explosions of coal dust in mines from 1891-1894, on the Royal Commission on coal supplies from 1902-1905, and on many other committees and government bodies. His publications included reports on Conditions of chemical change in gases (1884); Rate of explosion in gases (1893); Movement of flame in explosion of gases (1902); The ignition temperature of gases (1909), and many more. He edited the series Studies from the physical and chemical laboratories of the Owens College, Manchester, England from 1893 onwards.
Dixon joined the British Association for the Advancement of Science in 1879, serving as president of Section B (Chemistry) in 1894. In 1905, when this association met jointly with the South African Association for the Advancement of Science, he was part of its official delegation to this country, serving as one of the vice-presidents of Section B. On 17 August 1905 he read two papers at the meeting in Cape Town. The first, on "The propagation of explosions in gases" was a review of research and theories, including his own "sound wave" theory. The second, "On the atomic weight of chlorine", described his own experimental work in this connection.
Dixon was president of the Chemical Society from 1909-1911. He remained professor of chemistry at Owens College to 1922, when he was seventy years old, and was then appointed honorary professor. In his student days he played football for the University of Oxford and as a mountaineer undertook exploring climbs in the Canadian Rocky Mountains.