[2] In February 1848, Martin was nominated as a candidate for a by-election for the electorate of Durham in the New South Wales Legislative Council, but withdrew before polling day.

His most notable political achievement in his first eight years in office was to initiate the Parliamentary debate that led to the establishment of a branch of the royal mint in Sydney.

In October 1863, Martin was asked by the Governor of New South Wales to form a government with a mandate to address rising State deficits and rural unemployment.

As Premier and Colonial Secretary, Martin promptly introduced measures to reduce immigration and increase tariffs, but was unable to secure Parliamentary support for many of his reforms.

With limited achievements to its credit, the government suffered a substantial swing at the 1865 election and Martin stepped down to make way for the return of Charles Cowper.

Cowper was once again defeated in a no-confidence motion in December 1865, and in January 1866 Martin became Premier for the second time as leader of a coalition government with former rival Henry Parkes.

Martin retired from Parliament in November 1873 and was immediately named to the vacant position of Chief Justice of New South Wales.

James Martin died at home in Potts Point, Sydney on 4 November 1886 and was buried in St Judes churchyard in Randwick, NSW.