He unsuccessfully contested Edinburgh West in 1923 and 1924 before being elected as Member of Parliament (MP) for the seat in 1929.
When Labour came to power under Clement Attlee in July 1945, he was appointed Treasurer of the Household (Deputy Chief Whip),[4] which he remained until April the following year.
[5] He was sworn of the Privy Council in 1947[6] and raised to the peerage as Baron Mathers, of Newtown St Boswells in the County of Roxburgh, on 30 January 1952,[7] in recognition of his "political and public services".
Mathers was also Lord High Commissioner to the General Assembly of the Church of Scotland in 1946, 1947, 1948 and 1951, and was appointed a deputy lieutenant of Edinburgh in 1946.
[9] Lord Mathers married firstly Edith Mary, daughter of William Robinson, in 1916.