Fraser government (1975–1983)

In December 1975, MacKellar was first appointed to the front bench as the Minister for Immigration and Ethnic Affairs, a position he held until 1979, when he became Minister for Health and Minister Assisting the Prime Minister. In Opposition, MacKellar acted as Shadow Minister for Science.

MacKellar attracted some controversy over his handling of an incident involving the improper importation of a colour television set. In 1982, a ministerial staffer submitted an incorrect customs declaration form when arranging for the set to be imported. When this was discovered, a fellow Minister, John Moore, attempted a cover-up. Moore and MacKellar both accepted responsibility and resigned as ministers.^[2][3]

In Opposition (1983–1994)

Following the 1983 election defeat he returned to the frontbench as Shadow Foreign Affairs Minister, before being demoted to Shadow Science Minister after the 1984 election. After Andrew Peacock resigned he moved to the backbench.^[4]

He contested the Liberal Deputy leadership three times 1982, 1985 & 1987, finishing second to John Howard in 1982.

MacKellar resigned from Parliament on 18 February 1994, causing a by-election that was subsequently won by future Prime Minister Tony Abbott.

After Politics

After leaving politics MacKellar became Chairman of the Australia New Zealand Food Authority in 1998.^[5] He also acted as Chief Operations Officer of the Baker Medical Research Institute and Chief Executive Officer of the Plastics and Chemicals Industries Association. MacKellar also served as the president of the Melbourne-based National Ageing Research Institute.