He began his cartooning career while still in high school on the suburban weekly "The Darling Advertiser." The following year, his cartoons also became a regular feature of "The West Australian," making him, at seventeen, the youngest metropolitan daily political cartoonist in Australia.

In 1982, he was awarded a Queen Elizabeth II Jubilee Trust Award to study animation in the US. He spent some time at Mike Jones Film Corporation in Minneapolis before returning to Perth. In 1983, after seven years on "The West Australian," he joined "The Daily Sun" and then "The Courier Mail" in Brisbane.

From 1993 to 1994, he was a regular cartoonist for the Australian edition of TIME magazine. His work has also been featured in The Australian and The Bulletin magazines nationally.

His cartoons continue to appear in over 150 publications internationally through the Cartoonist's and Writer's Syndicate in New York, in papers such as The Times of London and The International Herald-Tribune.

In addition to his political cartoons, Sean writes and draws the nationally syndicated comic strip Beyond the Black Stump.

First published in 1988, the comic strip recently won the Stanley Award for Australia's 'Comic Strip Cartoonist of the Year' (2003) and the Gold Medal for Australia's 'Comic Strip of the Year' at the National Cartoon Awards, Rotary Club, Coffs Harbour.

In 2004, he received a Churchill Fellowship and travelled to the US and UK to further study animation.

Originals of his cartoons are included in private collections ranging from Steven Spielberg to the Vatican.