Leslie Marr was born at Aykley Heads in Durham City in 1922. He joined the RAF in 1942, serving in both the UK and in the Middle East. After leaving the RAF, he joined the classes of David Bomberg at the Borough Polytechnic, and in 1947 he exhibited with the Borough group at the Everyman Cinema Gallery. The year after, Marr was elected founder member and secretary of the expanded Borough Group and consequently frequently exhibited with the group.
Marr has travelled extensively and sought artistic inspiration from each place that he has visited, whether it be the Lake District in Cumbria or his trip to New Zealand in 1960. His most iconic and well-known works come from the time he spent in Scotland, particularly at Glen Etive, near Glencoe.
Marr primarily focuses on landscape and still life in a predominantly expressionistic style.