Nigel Pennick worked in scientific research for fifteen years in Cambridge, with periods at the Université Libre de Bruxelles, Belgium and the University of Guelph, Canada. In this time, he published twenty-nine scientific papers that described eight new species of marine algae. He lost his profession in 1985 when the institute was closed during government spending cuts and so he became a full-time writer and lecturer on history and folklore.In parallel with his scientific work at that time, he participated in folk traditions and the scene in Cambridge. In 1975 he founded the Institute of Geomantic Research, which published a journal and many occasional papers on all aspects of geomancy and earth mysteries. From the mid-1980s to the late '90s, he travelled widely and gave lectures and workshops at venues in Ireland, Holland, Germany, Switzerland, Austria and the United States as well as in Great Britain. He also organized and participated in several spiritual tours of ancient sacred places in England, Wales and Ireland. During this period, he was also writing books on subjects that include the runes, mythology, geomancy, ley lines, labyrinths, Celtic art and landscapes, traditional rites and ceremonies, folk magic and histories of certain underground railways in London.

He is also an artist in traditional media and stained glass, and has illustrated many of his books. In 2011 he had a one-man show of his Visionary Steeples artwork at Emmanuel Church, Cambridge. Currently, he plays music with The Traditional Music of Cambridgeshire Collective and throughout the year participates in the traditional calendar customs of Cambridgeshire, in 2009 having restored the custom of parading the May Day Garland through Cambridge.