1891 – Roy was born on the 23rd of August in Sydney and had his education at Chatswood and Hornsby public schools.
– He was taught music by Emanuel de Beaupuis, an Italian pianist living in Sydney, then briefly studied composition under Alfred Hill at the New South Wales State Conservatorium of Music.
1911 – Agnew was teaching the piano at Marrickville and beginning to compose ‘strikingly original works’, abandoning ‘the limitations of key and tonal relationship’.
1913 – He published "Australian Forest Pieces" for Piano.
1920 – Benno Moiseiwitsch played "Deirdre’s Lament" and the "Dance of the Wild Men" at a matinée two of his compositions at the Sydney Town Hall.
1923 – Agnew went to London where he studied composition and orchestration with Gerrard Williams.
1927 – His "Fantaisie Sonata" was played in London by William Murdoch, and published by Augener Ltd of London.
– The Arthur P. Schmidt Co. of New York issued five of his small pieces in book form, titled "Contrasts".
1928 – He returned to Sydney and in July played at a welcome-home concert at the conservatorium.
1931-1934 – Agnew performed his works at the Lyceum Club and at George Woodhouse’s studio, London, in Glasgow, and for the British Broadcasting Corporation.
1944 – In February, he joined the staff of the conservatorium but he died of septicaemia following tonsillitis on
the 12th of November and was cremated with Presbyterian rites.