The best-selling writer earlier this year paid just under £300,000 the Cairns of Coll, a string of Hebridean islands to the north of Coll.
The creator of the hugely successful No 1 Ladies' Detective Agency novels, speaking on BBC Scotland's Grand Tours of the Scottish Islands to be broadcast tonight, says: "There's something very special about islands. I find them very quiet and inspiring places."
McCall Smith, 65, says islands take their residents back to childhood. "As children we have a very small world around us, the world is small and I suppose we have some memory of the security of that.
"Later on, if one lives on an island which you can see all the boundaries of, then you have that sense of security - a sort of womb-like comfort."
l Grand Tours of the Scottish Islands is on BBC One Scotland, tonight at 7.30pm.