The Unitarian College was established in Manchester on 31 May 1854. Its original title was the Unitarian Home Missionary Board, reflecting its initial purpose and objectives. Prior to this, there had been a college in Manchester for the training of Unitarian ministers, but this moved from Manchester to London the previous year. Unitarianism being a relatively cerebral religion, its ministers tended to be drawn from the genteel classes, as did much of its clientele. Unlike other branches of Nonconformity, it was relatively unaffected by the evangelical revival of the late eighteenth and early ninetieth centuries, and Unitarians had refrained from populist preaching and emotional appeals to large audiences. However, the Religious Census of 1851, and the published report of its findings by Horace Mann drew the attention of the religious community in general to the absence of the lower orders from Sunday worship; this was particularly evident among the Unitarians. Preaching to working people and the poor was not entirely without precedent among Unitarians: they had been involved in initiatives in the 1830s and 1840s to undertake 'domestic missions' to the poor in Manchester. Following 1851, there was a raised awareness amongst all denominations of the need to make appeals to other classes, and among the more prescient it was realised that the failure of earlier efforts was related to the inability of middle and upper class evangelists to engage with those lower down the social ladder. In this context, John Relly Beard decided to set up an institution to train working class men with limited education to undertake Unitarian missionary activity amongst members of their own class and those below, despite reservation from some of their co-religionists.
Initially, Beard was the Principal of the Board and its Theological Tutor, and William Gaskell, the minister of Manchester's Cross Street Chapel, was Literary Tutor. The first classes were held in the homes of Beard and Gaskell, with lectures held in a room at the Cross Street Chapel. In 1857, they moved to premises in an old warehouse in Marsden Square, but were able to move to a more suitable home in 1865 following the building of a Memorial Hall in Albert Square to commemorate the bicentenary of the 'Great Ejection'. Beard resigned as Principal in 1874 on health grounds, and his place was taken by Gaskell, who despite his advanced age held the post for the next ten years.
Although the Board had been created to produce domestic missionaries rather that to supplement the production of ministers by the Unitarian College in London, the latter became its main function within a few years of its foundation. Domestic missions were to become indistinguishable from mainstream congregations, and the general shortage of Unitarian ministers across the country was met by the Board. Over time, the Board adopted stricter entry requirements and the training became increasingly rigorous. From the 1880s, students were encouraged to attend courses at the recently established Owens College, and its successor the Victoria University of Manchester. Early in the twentieth century, the Board (now 'College') was to be included in the University's Faculty of Theology, and the College adopted the matriculation examination of the University as its entrance requirement.
J. Edwin Odgers followed Gaskell as the Board's principal, to be replaced by Alexander Gordon in 1889, when its name was changed to the Unitarian Home Missionary College. Gordon was a distinguished historian and a regular contributor to the Dictionary of National Biography. His contributions ensured that Unitarian biographies had a disproportionate prominence among Dictionary entries. The College moved to a new home 'Summerville' in the salubrious suburb of Victoria Park in 1905. Following Gordon's retirement in 1911, Sydney Malone became principal, to be followed by Herbert McLachlan in 1921. Like Gordon, McLachlan was a prolific writer, and during his time as principal published histories of the College, its library and a detailed Register of the Students of the Unitarian College. Raymond Vincent Holt replaced Gordon as Principal in 1944, to be followed by Fred Kenworthy in 1955, and Arthur Long in 1974. Long retired in 1988. In 1984, the College became part of the Northern Federation for Training Ministry together with the Northern Baptist College, Northern College, Hartley Victoria College and the Northern Ordination Course which trained Anglicans and Methodists. The Federation changed its name to the Partnership for Theological Education in January 2000. Summerville was sold in 1985, when the College moved to its present home in Luther King House. Graham Murphy became Principal for a brief spell in 1990, to be followed by Leonard Smith. Ann Peart became the College's first woman Principal in 2002, retiring in 2009, handing over to Alex Bradley, the present Principal.