While still a student he was called up for service in the First World War in 1916, serving with the New Zealand expeditionary forces( NCEF) in Egypt, Palestine and Syria.

[3] Gillies had originally considered specialising in public health but chose instead a career in the developing surgical speciality of orthopaedics.

He returned again to the UK in 1940, acting as resident commissioner for the British Red Cross Society and the Order of St John of Jerusalem.

[8] Gillies was appointed a Knight Bachelor, for services to orthopaedic surgery, in the 1959 Queen's Birthday Honours.

[1][9] His name is commemorated in the Sir Alexander Gillies Gold medal which is awarded for distinguished and outstanding service to PENZ.

[10][11] Gillies married Effie Lovica Wooler (née Shaw) in Glasgow, Scotland, on 21 September 1920; she died in 1972.