John Frost's father died early in his childhood and he was brought up by his grandparents. He was apprenticed as a a bootmaker to his grandfather and left home at the age of sixteen to become a tailor, first in Cardiff, then Bristol and London. He returned to Newport in 1806 to start his own business, which became prosperous. He married and, over the course of eleven years, had eight children.
In 1821, Frost became embroiled in a dispute with a Newport solicitor, Thomas Prothero, over his late uncle's will. In a letter, Frost accused Prothero of being responsible for the former's exclusion from the will. Prothero sued for libel and Frost was ordered to pay £1,000. Frost then accused Prothero of malpractice. Again, Prothero sued for libel and again won. In February 1823, Frost was imprisoned for six months and told in no uncertain terms that further accusations against Prothero would lead to a longer sentence.
Frost turned his anger against Prothero's friends and business partners, notably Sir Charles Morgan, a major Newport landowner. In a pamphlet of 1830, he accused Morgan of mistreating his tenants and adovcated electoral reform as a means of bringing Morgan and others like him to account.
Establishing himself as a prominent Chartist, in 1835 he was elected as a councillor in Newport and appointed as a megistrate. The following year, he rose to be mayor. His aggressive behaviour was not stomached for long and he was forced to stand down as mayor the year after. The Home Secretary also removed his title of magistrate.
In 1839, Frost led a Chartist march on the Westgate Hotel in Newport. The rationale for the set piece confrontation remains opaque, although it may have its origins in Frost's ambivalence towards the more violent attitudes of some of the Chartists, and the personal animus he bore towards some of the Newport establishment who were ensconced in the hotel along woth the soldiers. One of his contemporaries, William Price described Frost's stance as being akin to "putting a sword in my hand and a rope around my neck."
He was arrested and charged with high treason. Found guilty, along with William Jones and Zephaniah Williams, Frost was sentenced to be hung, drawn and quartered, but a huge public outcry led to these sentences being commuted to transportation for life.
On reaching Tasmania, Frost spent three years working as a clerk, before becoming a school teacher for eight years. In 1854, he was granted a pardon on the condition that he never returned to Britain. Frost toured the United States lecturing on the unfairness of the British electoral system until 1856, when this condition was lifted and he retired to Stapleton. He continued to publish articles advocating reform until his death in 1877.
John Frost Square, in the centre of Newport, is named in his honour.
John Frost was also a British airborne officer, prominent in Operation Market Garden.