John married Margaret Williamson Brown on 5 Apr 1730 in Edinburgh Parish, Edinburgh, Midlothian, Scotland. Margaret (daughter of Rev. John Brown and Elizabeth Williamson) was born on 31 Jul 1705 in Abercorn, West Lothian, Scotland and St Cuthbert Edinburgh, Midlothian, Scotland; died on 8 Jul 1768. [Group Sheet]

1. Robert Johnston was born on 28 Jul 1732; died on 20 May 1797.
2. Rev Dr David Johnston was born on 26 Apr 1734 in Arngask, Perth and Kinross, Scotland, United Kingdom; died on 5 Jul 1824 in Edinburgh, Scotland.