William Crawford Williamson was born on November 24, 1816, in Scarborough, Yorkshire, England.

He was an English physician, naturalist, paleobotanist, and author. He studied medicine at University College, London, and during his studies, he acted as curator of the Natural History Society's museum at Manchester. After his graduation in 1841, he returned to Manchester to practise his profession. In 1851, he became Professor of Natural History at newly founded Owens College in Manchester and retained the chair of botany until 1892. Williamson was also a successful popular lecturer, especially for the Gilchrist Trust. He was elected a Fellow of the Royal Society in 1854, winning its Royal Medal in 1874 and delivering the Bakerian Lecture in 1877. He received an honorary LL.D. degree from the University of Edinburgh in 1883 and the Wollaston medal of the Geological Society in 1890. He published numerous articles and papers on paleobotany.

In 1842, he married Sophia Wood (1818–1872), and in 1874, he remarried Ann Copley Heaton (1842–). He died on June 23, 1895, in Clapham, London, England.