He inherited his fathers share of Killanaff Johnston was educated as a school teacher and had studied Civil Engineering at Trinity College. in 1846 he sold his share of the land at Killanaff to his cousin Richard Kells. Together with George Wood Kells he led a party of 19 relatives to Canada on the "Princess Alice". After being wrecked on the St. Lawrence River members of the family found their way to Toronto, Montreal and other locations on the St Lawrence River and Lake Ontario,. This group lay the foundation of the Kells presence in Canada and the USA. Jane died in 1849. Rod Christensen has identified a total of 15 children from the two marriages of Johnston.
Johnston married Jane HERBERT in 1835. (Jane HERBERT died in 1849.)