Cormack's first term in the Senate lasted only two years, during which he notably opposed the Menzies Government's attempt to ban the Communist Party.

Having begun his formal education in Scotland, Cormack attended a state school in Tumby Bay and then boarded at St Peter's College, Adelaide.

By 1934, he and his brothers John and William had acquired Koijak, a grazing property near Apsley, Victoria, close to the South Australian border.

At the 1947 Victorian state election, he managed William McDonald's campaign in the seat of Dundas, helping defeat the long-serving Labor incumbent Bill Slater.

[1] In a speech to the Melbourne University Liberal Club in April 1950, he urged Australia to take possession of Dutch New Guinea and populate it with white settlers, in order to pre-empt an Indonesian takeover.

[4] Cormack stood for the Senate at the 1955 election without success, and then the following year was defeated by George Hannan in a ballot to fill the casual vacancy caused by John Spicer's resignation.

The latter committee's report into financial malpractices received praise from the media, with The Age describing it as "probably the most incisive, impressive and influential document the Senate has ever produced".

[1] In the 1970 New Year Honours, Cormack was made a Knight Commander of the Order of the British Empire (KBE), "for long political and public service".

According to Alan Reid, Liberal MPs "filed in and out of Cormack's room, some from other states, as votes for Gorton were lined up during the leadership struggle".

[6] The Liberal Party senators formed Gorton's power base, and Cormack helped keep them on-side during William McMahon's leadership challenges.

[7] Following the retirement of Alister McMullin, Cormack was elected President of the Senate on 17 August 1971, defeating Labor's Justin O'Byrne by 31 votes to 26.

He crossed the floor a total of twelve times during his career,[13] and was a leading opponent of the Fraser government's 1977 referendum proposals; he chaired a campaign urging voters to vote "No" on all four questions.

[1] In March 1975, Cormack held a dinner party at his flat in Toorak, where he and other leading Liberals discussed how to remove Billy Snedden from the leadership.

Fraser was suspicious of Cormack's motives, particularly when he was asked to leave by jumping over the back fence – supposedly to avoid photographers who were waiting outside the front door.

Fraser suspected Cormack had actually arranged someone to wait by the back fence and photograph him climbing over, hoping to embarrass him and thus further Peacock's chances.

The station had strong ties to the Liberal Party, and its articles of association provided that any proceeds from its sale would be transferred to organisations with shared goals.

When the station licence was sold for $15 million in 1986, Cormack initially wished to divide the money between the Institute of Public Affairs, the Centre for Independent Studies, and other similar think tanks.

However, Liberal Party official John Calvert-Jones convinced him that the money should be used to establish a new entity, which was named the Cormack Foundation.