After the conclusion of the war, in addition to his personal business activities, he was often invited to fill various positions on state and federal government advisory bodies.

[1] Nathan also conducted trade negotiations for the federal government in the United Kingdom, serving as a commissioner to the British Empire Exhibition in London in 1924.

He was involved in the federal Advisory Council of Science and Industry (now CSIRO) from its beginnings in the early 1920s, and served a one-year term on its executive starting in 1927.

[4][5] Following the death of Athelstan Saw in November 1929, Nathan was endorsed as one of three Nationalist Party candidates at the resulting by-election for the Legislative Council's Metropolitan-Suburban Province.

[10] Completing the remainder of Saw's six-year term, he announced his retirement from the Legislative Council in December 1933,[11] and was replaced at the 1934 election by another Nationalist candidate, Hubert Parker.