Petty began working for the Owen Brothers animation studio in Melbourne in 1949, before moving to the UK in 1954. His cartoons were published in The New Yorker, Esquire and Punch. On his return to Australia in 1961, he worked at first for The (Sydney) Daily Mirror, The Bulletin and The Australian before joining The Age in 1976.

In 1976, the animated film Leisure, of which he was the director, won an Academy Award for the producer Suzanne Baker (the first Australian woman to win an Oscar). "When I got it, the Oscar went to the producer. We got a picture of it, a very nice gold-framed picture." (The Age, 22 June 2004)

Petty made a number of other award-winning animated films including Art, Australian History, Hearts and Minds and Karl Marx.

Petty also created a number of "machine sculptures" with the most famous being a piece known as "Man Environment Machine" (fondly known as the "Petty Machine") that was a feature piece of the Australian Pavilion at World Expo '85 at Tsukuba, Japan.

In 2007, he received the AFI Best Documentary Director prize for the documentary Global Haywire which he wrote, directed and animated, as well as the Best Documentary Sound prize ; this documentary tries to unravel the global pattern that leads to an understanding of how the world came to be as it is today, and is based on interviews with intellectuals, students and journalists.

Petty's 2008 book, Petty's Parallel Worlds, is a retrospective collection of editorial cartoons from 1959 to the present, street sketches done on assignment around the world, and etchings.

Those of Petty's cartoons that depict themes such as the economy, international relations or other social issues as complicated interlocking machines (that manipulate, or are manipulated by, people) have been likened to Rube Goldberg machines or Heath Robinson contraptions.

At the 2016 Walkley Awards Petty was recognised with the Most Outstanding Contribution to Journalism award.
Extract from this text a list of the major films, books, and art pieces of Bruce Petty's career.
* Leisure, a 1976 animated fillm
* Art, an animated film
* Australian History, an animated film
* Hearts and Minds, an animated film
* Karl Marx, an animated film
* Man Environment Machine, a machine sculpture featured at World Expo '85
* Global Haywire, a 2007 documentary
* Petty's Parallel Worlds, a 2008 book