Born in Geelong, Victoria, on 11th June, 1918, Alan Tregaskis was a pupil of Dr A.E. Floyd at St Paul's Cathedral in Melbourne. Tregaskis was Deputy Organist at St Paul's, and would continue to perform as an organist throughout his life, holding the position of organist to the South Australian and, later, Sydney Symphony Orchestras, as well as becoming well-known for his broadcast recitals.
After studying in Los Angeles and London, Tregaskis was awarded the Harding Prize for composition by the Royal College of Organists.
He moved to Adelaide after the Second World War, in which he had served as a pilot in the RAAF, and became the conductor of a number of choirs, including the Philharmonic, the University Bach Choir, and the ABC Adelaide Singers. He was the music master at Adelaide Boys High School and Methodist Ladies College, and also the organist of the Pirie Street Church. Tregaskis continued to work in similar fields after moving to Sydney in 1963, becoming Director of Music at Barker College, conductor of the Sydney University Musical Society, Director of the National Music Camp, and Principal Lecturer in Music at the Sydney College of Advanced Education.
He composed works for orchestra, choir, organ, chamber music and voice.
Alan Tregaskis died on the 4th of April, 1993.