He was also a man of letters who corresponded with well-known Victorian-era intellectuals such as John Stuart Mill.
In the early 1800s, Henry MacCormac travelled to Sierra Leone, where his brothers, Hon.
MacCormac served as a well-known physician and was a candidate for a chair at Queen's University in Northern Ireland.
After retiring from his medical practice, MacCormac engaged in literary and scholarly pursuits and corresponded with a number of important Victorian era intellectuals.
Henry MacCormac died at Fisherwick Place, Belfast, on 26 May 1886 at the age of 86.