Having retired from trade in 1839 he made a land deal purchasing the Ardintoul estate, with more land acquired at Inverinate on Loch Duich in 1844. To his own disappointment he was not a successful farmer on the sparsely-populated lochside, but proved a developer and builder. Matheson was elected as MP for Inverness Burghs in 1847, on repeal of the corn laws. From 1849 his London home was at no.16 South Audley Street, near Park Lane and joined the Reform Club on The Mall. He succeeded his uncle, as Liberal MP for Ross and Cromarty from 1868.