Colohan, John Fallon Sydney (1862–1932), physician and pioneering motorist, was born in Dublin, son of James Colohan, bank manager; nothing is known of his mother. He studied at the Edinburgh Medical School, and was admitted LRCP, LRCS (1892), and LRFPS (1892) (Glasgow), and undertook further training at TCD; St Thomas's Hospital, London; and Frankfurt University, Germany. He practised in London (1893–4) and at Long Ditton, Surrey (1895), before returning to Ireland and becoming medical officer of health at Athenry, Co. Galway (1896–7); he subsequently established a practice at Woodville, Blackrock, Co. Dublin (1897), and may also have been attached to other hospitals and public bodies. According to the Medical Directory, he was physician (1899–1922) to the Lynden convalescent home, Blackrock, Co. Dublin, though he claimed to have given up all medical practice by 1903. He was a JP for Co. Dublin from 1905.
He studied motor engineering in Germany, visited factories, and learned to drive in France. After the passing of the light locomotive bill (1896) – which raised the speed limit from 4 mph (6.4 kph) – he purchased a car, and is credited with being Ireland's first owner of a petrol-engined car, a 3.5 h.p. Benz Velo Comfortable, which he brought to Ireland (1896×98). It was exhibited at the Centenary of Motoring Exhibition (1986) and completed the London–Brighton runs of 1987 and 1988. A photograph (c.1898) of Colohan and his first wife in this car hangs in Hunter's Hotel, Rathnew, Co. Wicklow, and was represented on an Irish postage stamp in 1989.
He aroused public interest in the car in 1899 when he won his wager of driving 135 miles (217 km) from Dublin to Galway in twelve hours, possibly the first race against the clock in Ireland; he also took part in Ireland's first organised motor tour to Killaloe, Co. Clare (1900), and in a 1,000-mile tour (1901) in his 7 h.p. Daimler. In 1899 he negotiated with the Automobile Club of Great Britain and Ireland (RAC) to form the (Royal) Irish Automobile Club (1901), becoming a founder, a committee member, and its most active spirit. It organised the Gordon Bennett race – a major international racing event – held in Ireland in 1903; he did not take part, but took valuable photographs of the event. The programme described him as ‘about the first British subject to begin motoring’ and ‘the pioneer of motoring in Ireland . . . recognised even on the Continent as one of the leading motor experts’ (Cooke, 36), and pointed out that several of his inventions had come into use on well-known French and English cars. One of the sport's most enthusiastic supporters, he helped to organise a variety of driving events, supplied information to newspapers and motoring journals, and often publicised whatever car he owned for some superb attribute and then sold it. In 1901 he took ownership of a four-cylinder 24 h.p. Daimler, which he boosted to near 30 h.p., claiming that it was the most powerful car in the country.
Dynamic and entrepreneurial, he pursued the commercial advantages of the motor car and became a controlling partner of the coachbuilders John Hutton & Sons of Summerhill, Dublin (1898). He introduced the motor car to them and promoted their expansion into a full-scale motoring engineering works and stockist, which resulted in their becoming the leading motor car firm in Ireland.
Due to ill health, Colohan left Hutton's (1908) and bought the Grand Hotel, Malahide, Co. Dublin, where he lived with his second wife. He married first Emilie, apparently connected with the Sydney family of Penshurst Place, Kent, adding her name to his own. After her death he remarried, but his second wife's name has not been found, nor any evidence of children. Widowed a second time, he left Ireland in 1922 and eventually settled in Cookham Dean, Berkshire, where he was known as ‘the Irishman’ and ‘the mad doctor’. He owned the first wireless in the village and fitted it with an extra loudspeaker to relay church bells and the BBC Sunday service to his neighbours. Champagne formed a staple part of his diet and he was served the first half bottle on a silver tray at 11 a.m. each morning. A keen marksman, he was known to fire practice shots in the direction of some passing neighbour.
He died 27 August 1932 and was buried in St Peter's churchyard, Marlow, Berks. He bequeathed over £15,000 to two servants (Richard MacAllistair and his sister Maggie MacAllistair, originally from Malahide, Co. Dublin) and also to Irish charities and catholic institutions.