John MacCormac was also the founder of the first Free Will Baptist church in Sierra Leone and served as a member of His Majesty's Colonial Council and was styled with the title of 'Honorable'.
[2] He contracted a workforce of Temne labourers as well as Black colonists from the Sierra Leone some of whom also acted as overseers of the timber production process.
He also built a large stone house in the Sierra Leone hinterland and a spacious mansion worth £10,000 on the corner of Rawdon and Oxford Streets.
MacCormac and Campbell entered into a treaty with the Koya Temne on behalf of Governor Alexander Findlay the representative of the Crown colonial government.
[6] MacCormac was succeeded as the first pastor of the Church of God by his adopted son or ward, Thomas George Lawson, a Popo prince who served in the senior civil service of Sierra Leone.
John MacCormac was one of several European residents called to testify before the British Parliament in 1830 regarding the governance of Sierra Leone and the effectiveness of maintaining the Colony.
After suffering from a bout of illness, John MacCormac left Sierra Leone permanently on 21 June 1864 and settled in Barnsbury in Islington, London.