[1] Peter completed an apprenticeship as a joiner in Scotland[1] before emigrating to Sydney (at that time the principal city of the British colony of New South Wales) on 21 February 1855.

McCormick's musical ability led him to becoming the precentor of the Presbyterian Church of NSW, which gave him the opportunity to conduct very large massed choirs.

The Sydney Morning Herald described the music as bold and stirring, and the words "decidedly patriotic" – it was "likely to become a popular favourite".

Later under the pseudonym Amicus (which means 'friend' in Latin), he had the music and four verses published by W. H. Paling & Co. Ltd.[1] The song quickly gained popularity and an amended version was sung by a choir of 10,000 at the inauguration of the Commonwealth of Australia on 1 January 1901.

[1] In a letter to R. B. Fuller Esq., dated 1 August 1913, McCormick described the circumstances that inspired him to pen the lyrics of his famous song: One night I attended a great concert in the Exhibition Building, when all the National Anthems of the world were to be sung by a large choir with band accompaniment.

[4]McCormick died in 1916, aged 83, at his home, Clydebank, in the Sydney suburb of Waverley and he was buried at Rookwood Cemetery.

His obituary in the Sydney Morning Herald stated: "Mr. McCormick established a reputation with the patriotic song, Advance Australia Fair, which ... has come to be recognised as something in the nature of an Australian National Anthem".