Born in Haddington, East Lothian, William Gillies studied at the Edinburgh College of Art in 1916. After he graduated Gillies became a founder member of the 1922 Group. A year later Gillies was awarded a Travelling Scholarship and went to Paris to study with André Lhote and then went on to Florence.
During his life Gillies divided his time between teaching and painting trips both in Scotland and in Europe. In 1939 he settled in the Midlothian village of Temple and, although the surrounding landscape became his inspiration for many works, he is also well known for his paintings of still lifes and interiors.