Dr. Thomas Snell Jones, minister of Lady Glenorchy's Church in Edinburgh.
Missions attracted much of his attention, and in 1796 he took an active part in the formation of the Edinburgh Missionary Society, becoming its first secretary.
Ewing, who regarded the congregational system as more scriptural and more elastic than the presbyterian, had in 1798 resigned his charge as minister of Lady Glenorchy's Chapel, as well as his connection with the Church of Scotland.
Ewing married three times: in 1794 to Anne Innes, who died in 1795; in 1799 to Janet Jamieson, who died in 1801; and in 1802, to Barbara, daughter of Sir James Maxwell, bart., of Pollok, and stepdaughter of Sir John Shaw-Stewart, bart., of Ardgowan.
Ewing's third wife died 14 September 1828, in consequence of an accident at the Falls of Clyde, and her husband published a memoir, of which a second edition appeared in 1829.