Dillon was born in Belfast, he left school at the age of fourteen and for seven years worked as a painter and decorator, mostly in London.
His Connemara landscapes provided the viewer with context, portraits of the characters who worked the land, atmosphere and idiosyncratic colour interpretations.
In 1942, his first solo exhibition was opened by his friend and fellow artist, Mainie Jellett at The Country Shop, St. Stephen's Green, Dublin.
She had no formal training and she took Dillon and George Campbell as her mentors for decades and her work was of a similar surrealistic and primitive style.
[citation needed] In 1969, Dillon pulled his artworks from the Belfast leg of the Irish Exhibition of Living Art in purported protest during the Troubles against the "arrogance of the Unionist mob".
His picture was hanged alongside the donated works of T P Flanagan, William Scott, F E McWilliam, Deborah Brown and Carolyn Mulholland as well as more than twenty others.
Reihill expanded on this, pointing to a probably unrequited love for the painter Dan O'Neil and also highlighted Dillon's association with Basil Rákóczi and the White Stag Group's Kenneth Hall both strong gay connections.