Ewen William Alison was born in Auckland, New Zealand, on leap day, 29 February 1852, the son of Jane Cameron and her husband, Alexander Alison, a shipwright. The family moved to Devonport in 1854, and Ewen went to the Church of England School, North Shore. At the age of 13 he took his first job as a compositor with the New Zealand Herald. In 1867 he departed to join the Thames goldrush. The eldorado eluded him, but he made sufficient money to join his brother, Alexander, in a butchery partnership in Devonport the following year. To assist in this business, leases of the islands of Motuihe and Motukorea (Browns Island) were taken up for running stock. Later, Ewen set up in business on his own as an estate agent to assist in the disposal of land he had acquired in the Devonport area.
On 26 July 1876 Ewen Alison married Mary Ann Coleman at St Andrew's Church, Epsom. They were to have four sons and two daughters. Ewen was prominent in community affairs throughout his life. In 1876 he became a Takapuna riding member of the Waitematā County Council, and in 1886 a councillor of the Devonport borough. He served the borough as mayor from 1890 to 1895 and from 1902 to 1907 and served another term on the Waitematā County Council from 1900. After moving to Lochaber at the seaward corner of Hurstmere Road and The Promenade, Takapuna, he took office in 1913 as the first mayor of Takapuna. He was also MHR for Waitematā from 1902 to 1908 and sat in the Legislative Council from 1918 until 1932. In addition, he was a member of the Auckland Harbour Board from 1891 to 1895 and from 1911 to 1929; this activity was perhaps most closely related to his major achievement.
Ewen Alison's name will always be known in Auckland as that of the founder, guiding spirit and driving force behind the Devonport Steam Ferry Company Limited. With his brother, Alexander, he was instrumental in floating the company in August 1881 and they soon had a regular, inexpensive (6d. return) service operating in place of the somewhat mixed and unreliable concerns of the 1870s. Success did not come easily, however; the Alisons had to fight off a substantial challenge from George Quick's Eagle and Osprey in 1887–88 and cope with the depressed trading conditions of the late 1880s and early 1890s.
Careful and astute management saw them through, and by the turn of the century the Devonport Steam Ferry Company had control of all the major harbour crossings. In 1904 the Albatross was launched; this was the first of the two-decked double-ended wooden screw-ferries which were to become the Auckland standard. The first of the vehicular ferries which were to carry all the harbour traffic until the opening of the harbour bridge were also introduced. Further competition appeared on the Bayswater route from the Takapuna Tramways and Ferry Company in 1910. This was absorbed into the Devonport Steam Ferry Company in 1927 and in the same year the Alison brothers formed the North Shore Transport Company to take a similarly dominant role in the bus services on the North Shore. By the time Ewen Alison retired from active management of the Devonport Steam Ferry Company in 1934, it reigned unchallenged on the Waitematā Harbour, and he had been its chairman and managing director throughout its 53 years of existence.
Alison had numerous other business interests. He was deeply involved with shipping on the Kaipara Harbour, and from Auckland to Clevedon and to Ngunguru, near Whangārei. Since all these concerns relied on coal for motive power, Alison became chairman of both the Northern Coal Company and Taupiri Coal Mines, and president of the New Zealand Coal Mine Owners' Association. He was also prominent as chairman of a number of goldmining companies in Auckland. In 1912 he led Auckland employers in urging the establishment of a national defence fund, to be used in the event of union unrest or a general strike, and in 1913 helped to rally employers to defeat the waterfront strikers.
Alison's sporting interests were also extensive. He was a founder of the Takapuna Jockey Club and president until its amalgamation with the Auckland Racing Club, of which he was made a life member. The site of the former Takapuna club's racecourse at Narrow Neck was renamed Alison Park. He was also a founder and first president of both the Waitematā Golf Club and the Takapuna Bowling Club.
The drive and vision which Alison brought to his commercial activities were also to the forefront in his civic career. While mayor of Devonport he was responsible, against considerable opposition at the time, for the building of the borough water supply system from Lake Takapuna (Lake Pupuke), and also for the establishment of the foreshore reserves, the formation of King Edward Parade, the sealing of roads and footpaths and the acquisition of Rangitoto as a public domain. The clock tower at Devonport wharf was erected in 1928 as a mark of public esteem for Ewen Alison, while Alison Avenue in Takapuna and Ewen Alison Avenue in Devonport are other reminders of his service to the North Shore.
Ewen Alison remained a resident of Takapuna until his death at 31 Kitchener Road on 6 June 1945 at the age of 93. His wife, Mary Ann, had died in 1928. Alison was recognised as a doyen of the Auckland business world. He left a legacy to his native city of a ferry and bus service serving a string of shore suburbs, whose development he had done so much to foster. It was fitting that in 1951 the Devonport Steam Ferry Company renamed its largest vehicular ferries after the Alison brothers, who had run its affairs for over 50 years with conspicuous success.