Appointed Parliamentary Secretary to the Ministry of Finance in 1952, Lord Glentoran was the following year made Minister of Commerce, a post he held until elected to the Northern Ireland Senate in 1961. He was the Minister responsible for the destruction of much of the Great Northern Railway in Northern Ireland, when he unilaterally closed the Portadown – Armagh – Monaghan, Clones – Enniskillen -Belleek and Enniskillen – Omagh railway lines in 1957. Consequently, the privately owned Sligo, Leitrim and Northern Counties Railway linking Enniskillen to Sligo was forced to close. He was then Minister in and Leader of the Senate for three years, becoming its last speaker in 1964.
Lord Glentoran was said to have had such a "grand" demeanour that once, when visiting America, a Texas newspaper carried the headline "Irish royalty to visit Texas."