Benjamin Sutherland was born at Seaward Bush, Invercargill, on 22 October 1873, the son of John Sutherland, a farmer, and his wife, Mary Sutherland. After attending South School, Invercargill, he apparently taught for a while, but in 1890 he joined the railway service as a clerical cadet. Over the following 14 years he was stationed in Canterbury, Southland and Wellington. In 1904 he became a telegraphic instructor in Wellington. There, on 12 March 1906, he married Lucy Nicholas Humphries.
During the First World War Sutherland was active raising funds for patriotic purposes. In 1921, concerned at the rising price of consumer goods, he organised a co-operative shop among railway employees. The scheme failed to attract sufficient support and several wholesalers began exerting political pressure to have it stopped. Sutherland decided to start his own business and resigned from the railways. On 27 October 1922 he founded the Self Help Co-operative Limited, a retail grocery business. The venture was immediately successful and within a year there were seven Self Help shops in Wellington. Sutherland obtained a loan of £250,000 from Levin and Company, insuring himself and his two sons for £500,000 as security, and opened more stores. By the end of 1926 he had 18 shops in Wellington and by 1929 there were 56 throughout New Zealand. When Self-Help celebrated its 25th anniversary in 1947 it was the largest grocery concern in the country, with 200 shops.
In order to sell groceries at the lowest possible price, Sutherland kept expenses to a minimum: his shops were self-service (the first in New Zealand), no goods could be purchased on credit, there were no deliveries, there was no price fixing, and his customers were asked to bring their own wrapping paper and string. Certain groups, however, were less than happy at Self Help's success: in 1926 local merchants, manufacturers, grocers and chemists formed the Proprietary Articles Trade Association to fix uniform prices for their goods. Sutherland rejected price fixing and successfully challenged the legality of this move in court in March 1927. He fought off a further attempt to fix prices by another association of rival traders in May 1931.
To mark the 10th anniversary of Self Help in October 1932, Sutherland set up a liberal staff benefit fund. He also introduced profit-sharing schemes and quarterly and annual bonus payments as an incentive for staff and to reward co-operation. In May 1941 a £10,000 Fighting Services Trust was founded to help rehabilitate employees who had served overseas. Self Help also donated £40,000 to the war effort.
Sutherland's sons, Arthur and John, both joined him in the business. In 1941 Arthur founded the Sutherland Self Help Trust on behalf of the family: since 1963 the trust has distributed annual grants to deserving causes. Arthur died in 1942 and in December 1944 Benjamin established the Arthur Sutherland Self Help Staff Fund to provide superannuation and life assurance for employees. A women's marriage bonus and an educational bursary scheme were started in January 1946.
Benjamin Sutherland was prominent in the Wellington Chamber of Commerce and the Wellington Employers' Association, of which he was president in 1936–37. He was also active in the New Zealand Employers' Federation, representing it at the International Labour Organisation conference in New York in 1941. A keen cyclist in his youth, he served for many years on the Wellington Amateur Athletic Association and was largely responsible for the appointment of the first professional athletic coach in New Zealand.
From 1928 the Sutherlands lived at Homewood, a large property in Karori. They employed A. W. Buxton and Sons, the Christchurch landscape company, to design and lay out a new garden. No expense was spared: between 12 and 20 men worked on the project for two years. New features included three walled gardens, grottos and glow-worm caves and a huge white-tiled swimming pool. There were 18 aviaries containing hundreds of birds. Sutherland wanted a fountain with coloured lights, but his wife was not keen. However, he had one installed when she and their daughter, Jean, were in England on a trip. The Sutherlands frequently opened Homewood to the public in aid of specific charities.
Benjamin Sutherland died in Wellington on 1 January 1949 after a fall at his home. He was survived by his wife, daughter and son. In 1958 Homewood became the residence of the British high commissioner and in 1974 Self Help was sold to various other grocery concerns.
Sutherland had left the railways after an undistinguished career with a staff card classifying him as 'a man with no initiative'. He became one of New Zealand's most innovative and enlightened businessmen. He revolutionised the retail grocery trade, introducing new methods of marketing and setting the stage for strong competition among dealers. He established numerous benefit schemes for his staff and gave generously to the wider community. Few men have had more initiative.