After completing his studies at the Edinburgh College of Art and Edinburgh University during 1932-37, Gear set off to Paris to study at the Académie Colarossi under Fernand Léger. Subsequently, he travelled and exhibited extensively in Italy, Greece and the Balkans. Gear returned to Paris in 1947 and became associated with the CoBrA group. In Paris, Gear met Hans Hartung, Pierre Soulages and Serge Poliakoff and became part of the 'Art Informel' movement, which encompassed a wide variety of styles and approaches to Abstract Painting. Gear would achieve overnight fame when he was awarded the Festival of Britain Prize in 1951. His paintings of abstract organic shapes in vibrant colours are considered a significant contribution to European 20th century painting. Gear remained an Abstractionist until his death in 1997.

Gear's work has been exhibited worldwide and is included in the collections of many museums around the world, including: Tate Gallery, London, Museum of Art, Tel Aviv, The Art Gallery of Ontario, Toronto, The National Gallery of Canada, Ottawa, The Scottish National Gallery of Modern Art, Edinburgh and the Museum of Modern Art, New York.