Samuel Ironside is said to have been born on 9 September 1814 at Sheffield, Yorkshire, England, and was baptised on 16 October. He was the son of Mary Bradbury and her husband, Samuel Ironside, who had been successively clerk, collector of debts, real estate agent and accountant. Samuel was educated at the Lancastrian school in Sheffield, and trained as a cutler before entering Hoxton Wesleyan Theological Institution. He married Sarah Eades on 24 August 1838 at Sheffield; they were to have seven children. Ironside was ordained and set apart for missionary work on 14 September 1838 in Wesley's Chapel, City Road, London.
Ironside left England for New Zealand on the James on 20 September 1838, arriving at Hokianga on 19 March 1839. His first appointment was at Mangungu, on Hokianga Harbour. In five months he became reasonably fluent in Maori. He witnessed the signing of the Treaty of Waitangi at Waitangi and defended its integrity all his life. In 1840 he travelled overland from Kawhia to Wanganui to select sites for new mission stations. He then moved to Port Underwood in the Marlborough Sounds in December 1840. There he established a flourishing mission from which he buried the victims of the Wairau affray in 1843 and laid the foundation of the Wesleyan church in Nelson and Marlborough. He was a trusted mediator between Maori and settlers during his ministry at Wellington from 1843 to 1849. From 1849 to 1855 he was stationed at Nelson, and from 1855 to 1858 at New Plymouth, where he supported the mediating work of fellow missionaries Henry Turton and John Whiteley.
Ironside's literary interests led to the publication in 1848 of the New Zealand Evangelist, of which he was joint editor with John Inglis, and the commencement in 1865 of a South Australian Wesleyan magazine. He translated into Maori several of Wesley's sermons, prepared a history of Wesleyan missions in New Zealand and, with James Watkin, was commissioned to prepare the final volume of a Maori biblical and theological dictionary.
Ironside's importance for New Zealand stems from the success of his mission station in Port Underwood. The friendship he had established with Rawiri Kingi Puaha, nephew of Te Rauparaha, and with other Maori leaders, placed him in a unique position to mediate between Maori people and the Port Nicholson settlers. He publicly defended Puaha's character against attacks from settlers and in 1845 promoted, against settler opposition, a gathering at Porirua as a means of sustaining Christian sympathies among the Maori people of the former Port Underwood mission station. His presence, together with that of the Reverend Octavius Hadfield, was crucial for the defence of the area.
Samuel Ironside played an active role in community affairs. He encouraged education among both Maori and settlers. While supporting the Nelson School Society, he strongly advocated state aid for denominational schools and opposed a purely secular system on the grounds that knowledge must be controlled by a Christian value system. He took his place on the public platform as a lecturer for the Evangelical Alliance and as a member of the Nelson and Taranaki institutes; he gave the first two scientific lectures at the Taranaki Institute, on pneumatics in 1856, and on the solar system in 1857. Strong sympathies with settlers who had come to New Zealand to improve their lot in life led Ironside to participate in the supervision of the Nelson Working Men's Freehold Land Association, and its subsidiary, the Sheep Association. When the ventures failed because of rising land prices, Ironside and others called for a full inquiry, which led to Mathew Richmond's withdrawing his candidature for the superintendency of the province in 1852. Ironside's involvement in these activities may have had its roots in his family background; his brother Isaac was an active Chartist in Sheffield.
Although Ironside had not been a total abstainer in his earlier years, the drunkenness prevalent in early Nelson, the too liberal granting of licences for public houses, and the deaths resulting from drunken behaviour, led him to support temperance. Although not always in agreement with his contemporaries in matters of education, the advancement of workers, and the temperance issue, he was held in high esteem by Nelsonians of every level of society.
Ironside's transfer in 1858 to Australia, where he served in Sydney, Adelaide, Hobart, Melbourne and other towns, deprived New Zealand of his ripest years. Samuel Ironside died at Hobart on 24 April 1897; his wife predeceased him.