David Buddo was born on 23 August 1853 in Edinburgh, Scotland, the son of Euphemia Stevenson Dorward and David Buddo, a surgeon in the Indian civil service. A rural childhood gave him a lifelong love of farming and country life. He was educated in Kincardineshire, and at a private grammar school in Perth, Scotland. He also served in the Kincardineshire Volunteers.
After training as an engineer in Perth, Buddo emigrated to New Zealand about 1874 and set up his own engineering firm in Christchurch. Two years later he sold it and bought a farm at Ellesmere. Over the next decade he prospered by growing grain. His first public office was as a member of the Springs Road Board (1884–87). Buddo was a Presbyterian and a regular churchgoer all his life. On 22 December 1886, at Irwell, he married Janet Rollo, and then took her on a tour to North America, Europe and the British Isles.
In 1891 Buddo and his family moved to a larger property at Fernside, near Rangiora in North Canterbury, where he became a notable breeder of Border Leicester sheep and draught-horses. With a manager to run the farm he bought a large house in King Street, Rangiora, and entered politics as a Liberal, winning the Kaiapoi seat in 1893. In later years he was proud of his association with the humanitarian and industrial legislation of the Liberal era. He was not a showy speaker, but clear and incisive.
After losing his seat to Richard Moore in 1896 David Buddo immersed himself in local-body work and was elected to no fewer than three boards in 1897. He served on the Mandeville and Rangiora Road Board until 1900 (as chairman in 1898–99), the Lyttelton Harbour Board until July 1907, and the North Canterbury Education Board until 1909 (as chairman 1901–2 and 1906–7). He also found time to be a captain in the North Canterbury Mounted Rifle Volunteers, in 1902–3.
In 1899 Buddo won back the Kaiapoi seat, and held it, with only one interruption, until 1928. He was long remembered as one of the district's most popular and effective representatives. In Kaiapoi he was instrumental in getting the town a new railway station; he opened a new post office in 1904 and the technical school in 1911; and he laid the foundation stone of the Coronation Library in 1912. In Rangiora he secured government subsidies for a public swimming bath and a new concrete bridge over the Ashley River, both opened in 1912. Janet Buddo loyally supported her busy husband, and was invited to plant the Queen Victoria Memorial Oak in Victoria Square, Rangiora, in 1902. Buddo was a long-serving director of the New Zealand Farmers' Co-operative Association, and later said he regarded this work as 'one of the most useful things he could do for the farming community'.
David Buddo was a member of Sir Joseph Ward's 1909–12 cabinet as minister of internal affairs and minister of public health. Described as 'squarely built, alert and dapper', with a 'nicely brushed' grey beard, he was regarded as a middle-of-the-roader unlikely to evoke strong opposition. Buddo was a diligent and efficient minister but made no great impact on national politics. He was a good debater who was always well prepared, and his advice was often sought by new members, who found him 'a veritable storehouse of knowledge'.
In 1916 Buddo's keen advocacy of farming interests led to his election to the board of governors of Canterbury Agricultural College at Lincoln. He remained a member until his death. In 1926 he lobbied hard in Wellington on behalf of the board, when the government was planning a North Island agricultural college and the college's future seemed in doubt. Perhaps his finest speech in Parliament was a masterly summary of what had been achieved at Lincoln with slender resources. Buddo led several deputations to the prime minister, and Canterbury's college was spared.
Buddo's re-election to Kaiapoi in 1922 (he had been defeated in 1919) demonstrated the strength of Liberal support in rural Canterbury, but it was also a measure of his personal popularity. In 1923 he secured amending legislation that enabled the Kaiapoi Borough Council to launch a new housing scheme, and in 1928 he played a key role in negotiations that finalised control of electricity reticulation north of the Waimakariri River. A scheme for subdivision south of the river appears on a map of Christchurch in 1926 as the 'Buddo Settlement', but the project never eventuated. Buddo retired from politics in 1928. He was appointed to the Legislative Council in 1930 and remained a member until June 1937.
On 8 December 1937 Buddo collapsed in the office of the Christchurch Gas, Coal and Coke Company and died in the ambulance on his way to hospital. Parliamentary tributes suggest that he was a respected and much-liked politician, regarded as an authority on all farming matters and a model local member for the way he looked after the interests of his constituency. Prime Minister Michael Joseph Savage described him as 'a Liberal of the Old School,…an earnest man and a good friend' who had worked hard to improve the lot of farmers. In Rangiora he was remembered as 'a lively, intelligent and popular little man', a familiar figure at all public functions in the town for nearly 40 years.
Janet Buddo died in 1945; the Buddos were survived by two sons and one daughter. A cousin, Helen, orphaned in infancy, was also raised as one of the family. Both sons later settled on a block of land bought by David at Poukawa near Hastings; his son-in-law also bought a farm near Poukawa. Thus the descendants of one of Canterbury's best-known farmer-politicians of the Liberal era have ever since been associated with Hawke's Bay.