[5] Following his mother's death, McCombs was selected as her replacement as the Labour Party candidate for the Lyttelton electorate.

[6] In 1936, McCombs was appointed to the Canterbury University College Council, and he remained a member until 1947, when he became Minister of Education.

[9] In the centennial history of the university, it is stated that "Canterbury has never enjoyed greater ministerial support than it did from McCombs".

[10] Following the defeat of the Labour government McCombs was nominated to stand for the deputy leadership in January 1951 following the death of Peter Fraser.

[14] He was a member of Rotary International and belonged to the Christchurch South club, of which he was the district governor of in 1967.

[15] After being recalled early from his posting to London, to ease the retirement of outgoing Deputy Prime Minister Hugh Watt, he was appointed chairman of the Committee on Secondary Schools from 1975 to 1976.

He gained a wealth of knowledge on the subject of planning and the complex laws that governed it and, according to Deputy Mayor Rex Lester, he "...always seemed to have the uncanny ability in coming up with the right decision.

[18] McCombs was appointed an Officer of the Order of the British Empire, for services to education, in the 1971 Queen's Birthday Honours[19] and a Knight Bachelor in April 1975.