The current building replaced the original Anglican chapel, which was built in the 1840s, with the foundation stone laid by Bishop George Selwyn and designed by Frederick Thatcher, a London-trained architect, and one of the first settlers arriving in New Plymouth in 1843.

The beginnings of Christianity in the area came as a result of the need to provide the familiar spiritual and cultural institutions of home to the settlers, as well as missionary services to the Maori population.

The advent of the Taranaki Wars and other factors, however, delayed the building of a permanent structure until 1872 when board, battens and shingles replaced the existing rustic cladding materials.

The additions to the simple original Holy Trinity Church building have included Gothic Revival features such as transepts, an apse, lancet windows and high steep gables.

The association of the place with Bishop Selwyn who is of national historical significance, and figures of considerable local importance, such as Reverend Bolland and Archdeacon Govett, further increases its relevance as these people shaped the Church in the mid-nineteenth century, not to mention that the original building was a rare survivor of the Taranaki Wars.

Holy Trinity Church also has architectural importance because of its associations with Frederick Thatcher and significant local architects, James Sanderson and Francis John (Frank) Messenger.