He grew up in Toronto, where he began a career as a commercial artist. In 1938 he emigrated to the USA to work with The Walt Disney Company, where he was a story writer and collaborated on several classic Disney films. Turning freelance in 1948, he did cartoon illustrations for magazines and advertising campaigns, notably for the Ethyl Corporation.

Gurney is best known for his humorous illustrations in books for children and adults. He illustrated Punctured Poems (1971) by Richard Armour; How to Live with a Neurotic Dog (1960) (text by Stephen Baker); How to Live with a Calculating Cat (1962) (text by William Nettleton); an edition of Sportsmanlike Driving (1965), a textbook published by the American Automobile Association; and many other titles, whose total sales number in the millions.