He was ordained as a priest in 1852 and served as curate of Haslingfield near Cambridge, 1851โ4. In 1855, he went to Natal with Bishop Colenso and served as Archdeacon of Natal. They worked among the English settlers till 1859 when he returned to England briefly to raise support for more direct missionary work.[3] In 1860, Mackenzie became head of the Universities' Mission to Central Africa and he was consecrated bishop in St George's Cathedral, Cape Town, on 1 January 1861. Following David Livingstone's request to Cambridge, Mackenzie took on the position of being the first missionary bishop in Nyasaland (now Malawi); he was called at the time (Missionary) Bishop in (or of) Central Africa.
Moving from Cape Town, Mackenzie sailed with Livingstone up the Zambezi and Shire rivers with a small group, including Horace Waller, to start work. He arrived at Chibisa's village in June 1861 with the goal to establish a mission station at Magomero, near Zomba, while Livingstone continued with his expedition. Mackenzie directly opposed the slave trade causing the enmity of the Yao. He worked among the people of the Manganja country until January 1862 when he went on a supplies trip together with a few members of his party. The boat they were travelling on sank and as their medical supplies were lost, Mackenzie's malaria could not be treated. He died of Blackwater fever on 31 January 1862 on an island in the Shire River, and was buried at Chiromo. Livingstone erected a cross over his grave a year later.
Awdry, Frances (1904) [1878]. An Elder Sister: a short sketch of Anne Mackenzie, and her brother the missionary bishop (3rd ed.). London.{{cite book}}: CS1 maint: location missing publisher (link)