Jean Michel Camille Malfroy, usually known as Camille, was born at Macornay, Lons-le-Saunier, Jura, France, on 23 March 1839. He was the son of Jean Baptiste Malfroy, a miller, and his wife, Josephine Vuidard.
With his father and Jules Cézar, the eldest of his three brothers, Camille joined the rush to the Victorian goldfields in the 1850s. He appears to have arrived in New Zealand in the early 1860s. In 1866 he was admitted to the Ross Oddfellows' Lodge, of which he was trustee for 15 years. On 1 July 1874 Malfroy, then manager of the Totara and Jones's Creek Water Race Company, married Ellen Alice Jones at Ross. Although they had no children of their own, the couple unofficially adopted a daughter, May, born Mary Searle at Donoghues, Ross, on 14 March 1880. In adult life May reverted to her birth names.
Naturalised on 7 May 1878, Malfroy was that year elected first mayor of Ross and appointed a justice of the peace. In 1876 he had unsuccessfully stood for the Totara riding of the Westland County Council; his challenge of the ballot count at the Donoghues polling booth failed to alter the result.
During his years on the West Coast goldfields, Malfroy was associated with the Mont d'Or Gold Mining and Water Race Company and the Ross United Gold Mining Company, variously as mining manager, mechanical and hydraulic engineer and director. He gained a reputation for ingenuity in designing water races and mine pumping equipment; it is claimed that he installed at Ross the first large hydraulic pumping plant in New Zealand. Malfroy patented three of his inventions: a centrifugal minerals separator, a reversible turbine for winding purposes, and sluice ripples made from cut railway lines.
In 1886 Malfroy's career took a new direction when he accepted appointment by the Crown Lands Department as engineer in charge of works connected with the Rotorua wharf and the town water supply. In addition, Malfroy was responsible for recording the changes in lake level and thermal activity which had occurred after the Tarawera eruption of that year. In addition, Malfroy was overseer of works associated with the Rotorua Sanatorium.
Malfroy soon proved his engineering and organisational skills, and he was appointed to mount and take charge of New Zealand's exhibits at the 1889 Exposition coloniale in Paris. Here he served both as exhibition juror and exhibitor, winning a silver medal for his entry of Maori clothing. On 30 October 1889 he was made a chevalier de la Légion d'honneur. After the exhibition Malfroy visited English and European spa facilities with a view to improving those in New Zealand.
Malfroy returned to Rotorua and in 1891 became chairman of the Rotorua Town Board. He had been first elected to the position in 1888, but stood down during 1889–90. He held the position from 1891 until his death, except for a break in 1893 when he was sent to report on the thermal potential at Hanmer and South Westland, and another period of leave in September 1895. As a local politician Malfroy was diplomatic in his dealings with Maori. He facilitated the purchase of Hinemihi meeting house for the retiring governor, Lord Onslow, in 1892, and gained permission for the removal of Maori graves impeding road realignment at Ohinemutu.
In his capacity as an engineer, however, his relationship with Maori may have been less successful. At Whakarewarewa there was interference with departmentally authorised works around Pohutu geyser, which Malfroy had manipulated into playing regularly. However, his experiments in accelerating silica deposition to form artificially extended terraces around Waikite geyser were not obstructed.
Malfroy had suspected that barometric pressure influenced geysers, but showed by experiment that the release of hydrostatic pressure stimulated geyser action. A member of the New Zealand Institute since 1876, he delivered a paper to the Auckland Institute in June 1891, 'On Geyser-action at Rotorua'; a model geyser of his design was displayed to the same group the following year.
Malfroy made numerous improvements to the Rotorua Sanatorium amenities. He invented a non-corroding, water-powered wooden clock to help bathers gauge their bathing time, a hydraulic 'ejector' to regulate water levels, and a device to enable bathers to control bath temperature. He maintained and improved the battery system of the galvanic baths, experimented with non-corrosive pipes, and introduced what was possibly Rotorua's first sprinkler system for the Sanatorium lawns. During this time Malfroy also patented an automatic sewer-flushing tank. His best-known invention was a trio of artificial geysers. The Malfroy Geysers, as they were known, were capable of playing to a height of 12 metres; they were formed by directing hot water from Oruawhata springs through pipes fitted with regulating valves.
Malfroy early realised the tourist potential of Rotorua's thermal regions. He advocated a comprehensive scheme of development for a 'therapeutic thermal establishment' instead of piecemeal additions to the sanatorium. With tourism in mind he supervised the planting of lawns, shrubs and trees, the improvement of path and road access, and the construction and maintenance of comfortable and efficient bathing facilities. An active promoter of bathing facilities for women, he officially opened the women's swimming bath in 1896. Within the community he took an interest in the formation of a local fire brigade, was a member and at one time chairman of the Rotorua Jockey Club, and was both trustee and treasurer of the Rotorua Brass Band.
Troubled by a persistent lung ailment, Malfroy had spent some months during 1895 in the drier climate of New South Wales. However, his illness worsened and he died of tuberculosis at his Rotorua home on 6 January 1897. He was survived by his wife and adopted daughter. A large monument marks his grave in the Rotorua cemetery.
Reputedly courteous and helpful, undeniably ingenious and versatile, Camille Malfroy pioneered the harnessing of natural steam, helping to further knowledge of Rotorua's geothermal systems. He did much to develop the reputation of Rotorua as a tourist centre in the country he readily acknowledged as his home.