Upon its opening in 1843, John Farrar became classics tutor at the Wesleyan Theological Institution at Richmond, Surrey, where he spent fourteen years.

On the foundation of the Wesleyan Theological College at Headingley, Leeds, in 1868, he became the first governor, and retained the chair until failing health compelled his retirement in 1876.

During his residence here, the jubilee of his ministry occurred, when he was presented with an organ for the college, where a marble bust of himself now preserves the memory of his connection with the institution.

He lived to take part in the Wesleyans' closing (June 1883) and refounding (September 1883) of Woodhouse Grove School, to widen its intake of pupils.

Farrar wrote several books, including two religious dictionaries, one dealing with the Bible and its contents, the other referring to ecclesiastical events.