Born to a lower-class household in Monmouthshire, Wales, Price trained as a doctor in London, England before returning to Wales, becoming interested in the Chartists' ideas regarding equal democratic rights for all men. Following their failed 1839 uprising, he escaped government prosecution by fleeing to France, where he became convinced that an ancient prophecy predicted that he would remove Wales from English rule.
Returning to Wales, Price tried reviving what he believed to be the religion of the ancient druids, the Celtic Iron Age ritual specialists of western Europe. In doing so, he became one of the most prominent proponents of the Neo-Druidic movement, something that had been developing since the Welsh nationalist Iolo Morganwg's activities in the late 18th century. After cremating his dead son in 1884, Price was arrested and put on trial by those who believed cremation was illegal in Britain; however, he successfully argued that there was no legislation that specifically outlawed it, which paved the way for the Cremation Act 1902. Upon his death, he was cremated in a ceremony watched by 20,000 onlookers.
Known for adhering to such principles as equal democratic rights for all men, vegetarianism, cremation and the abolition of marriage, some of which were highly controversial at the time, he has been widely known as an "eccentric" and a "radical". Since his death he has been remembered by some people as "one of the great Welshmen of all time". A permanent exhibition and statue dedicated to him being was opened by these people in the town of Llantrisant, where he had lived for much of his later life.