He was born on 5 October 1830 in the manse, Garvock in northern Scotland the son of Rev James Mitchell, the local minister, and his wife, Margaret Gordon.
In May 1854 he was licensed to preach by the Presbytery of Fordoun, but almost immediately thereafter (July) was ordained as Rev Dr Barry's assistant at St Enoch's Church in Glasgow.
[3] In 1872, following the Education Act of that year, the Dr Bells School in Leith became thereafter funded by the state and its previous endowment became unused.
In the same year he organised a free soup kitchen and the building of Leith Model Lodging House (for homeless men) on Parliament Street.
[1] In 1901, at the very advanced age of 71, he was elected Moderator of the General Assembly of the Church of Scotland in succession to Rev Norman MacLeod of Inverness.
A memorial to Mitchell was added in the south-east corner of South Leith Parish Church in 1912, designed by Sir Robert Lorimer.