John McLean was born in Portsay, Banffshire, Scotland. He came to Canada after graduating from the University of Aberdeen and was ordained a priest in 1858. In 1866 he went to Winnipeg, then a village of 300, to assist his university friend, Bishop Robert Machray and become rector of St John’s Cathedral.
In 1874, largely through the representations of Bishop Machray, 2 new dioceses of Saskatchewan and Athabasca were created. The diocese of Saskatchewan covered the territories of Saskatchewan, Assiniboia and Alberta. John McLean was made Bishop of Saskatchewan and on May 3, 1874 consecrated in Lambeth, England.
Bishop McLean began his work in the chiefly Indian diocese with no church and a staff of one priest, one native deacon and a catecist. He established Emmanuel College in 1879 to train natives for church work and at the time of his first Synod August 31, 1882 held in Prince Albert there was a clerical staff of 16.
Bishop McLean throughout his episcopate had been very successful in raising funds from England and Eastern Canada. These funds were used to run all but 4 of the 22 missions in place at the time of John McLean’s last Synod.
Bishop John McLean travelled the diocese extensively, in winter by dog-sleigh and in summer by open boat. It was on the trip back from the 1886 Synod that he was taken ill and died at Edmonton, 7 November 1886.