Baker was born in Guisborough in North Yorkshire, the son of John and Mary (née Gilbert) Baker, and died in Kew. He lived in Thirsk (North Yorkshire) until 1864 when the drapers store owned by his family burnt down. The place where he lived in the town, now called Bakers Alley, is marked by a blue plaque which was unveiled in 2005 by Professor Simon Owens who, like his renowned predecessor, was then Keeper of the Herbarium at Kew.
He was educated at Ackworth School and Bootham School, York, both being Quaker schools.
He subsequently worked at the library and herbarium of the Royal Botanic Gardens, Kew between 1866 and 1899, and was keeper of the herbarium from 1890 to 1899. He wrote handbooks on many plant groups, including Amaryllidaceae, Bromeliaceae, Iridaceae, Liliaceae, and ferns. His published works include Flora of Mauritius and the Seychelles (1877) and Handbook of the Irideae (1892). Baker issued several exsiccata-like series, among others the series Plants of North Yorkshire and Herbarium of British Roses [Herbarium Rosarum Britannicarum].
↑Britten, James (1920). Britten, James (ed.). "John Gilbert Baker (1834–1928)". The Journal of Botany, British and Foreign. 58. London: Taylor and Francis: 233–238. Archived from the original on 18 July 2022. Retrieved 18 July 2022– via BHL.
↑Woodland, Jenny (2011). Bootham School Register. York, England: BOSA.