Tanner began his career at the Daily Telegraph in 1942, where he worked under the mentorship of Art Director Tommy Hughes, Senior Artist Frank Broadhurst and William Pidgeon (q.v.). At 18, Tanner was sent to Japan by Tele editor Brian Penton to work at the British Commonwealth Occupation News (BCON) as a cartoonist. While there, Tanner developed an interest in Japanese art that had been instigated by William Pidgeon.
On his return to Australia, he joined the A. M. magazine as an illustrator before returning to the Daily Telegraph and Sunday Telegraph, where he had his first assignment as a political cartoonist. He later became Art Director at the Bulletin. When he drew a controversial cartoon of Sir Henry Bolte, then premier of Victoria, to illustrate Editor Peter Coleman's article against capital punishment, Sir Frank Packer pulped the entire edition of the magazine. ABC television ran a story on the banned cartoon and editorial, to highlight the issue of censorship of the press.
Tanner won the Cartoonist of the Year award in London in 1960 whilst working for the Daily Sketch, followed by two Walkley Awards in Australia in 1962 and 1965. Graham Perkin, Editor of the Age, appointed Tanner Chief Political Cartoonist, a position he held for thirty years until he retired in 1997. He also had a popular Saturday column, 'Tanner with Words'. In 1999, he received a Golden Quill Award for Lifetime Achievement in the Arts.
Apart from a prolific career as a cartoonist, Tanner co-wrote several books on black and white art. He made an animated film called Letter to a Vandal and was an actor and set designer for the New Theatre from 1946 until 1955. As a child he appeared in a number of films including comedian George Wallace's Gone to the Dogs.
Several compilation books of Tanner's cartoons have been published.
