“Fleety” began his acting career in the early 1980s with several performances in Australian television series and telemovies. He starred in Matthew and Son alongside Nicole Kidman in 1984, and then played the role of "Delivery Man 2" in an episode of Prisoner in 1985. Fleet went on to star as Lt Scott Harris in the Australian miniseries A Thousand Skies.

In 1988, after a guest appearance in The Flying Doctors, Fleet took on the role of Dave Summers in the Australian soap Neighbours. His most dramatic sequence in this program involved killing the popular character of Daphne in a car accident. Fleet then appeared in the popular Australian sketch show Full Frontal.

Since then, Fleet has been a regular stand-up comedian around Australia, and has appeared on many TV and radio comedy programs, including The Comedy Channel's Stand Up Australia! He was the announcer and narrator for the comedy series Real Stories (Network Ten), and has provided the voice of "Sandy" the Yellow Labrador in TV commercials for the Home Hardware retail chain.

From 2006 – 2007, Fleet was often heard on Triple M's Get This radio program as a frequent guest co-host alongside Tony Martin, Ed Kavalee, and Richard Marsland.

In 2011, Fleet released Bootlegs and Jumperpants DVD, containing segments of some of his best known performances.

In 2015, Fleet starred in the Australian cult-classic underground zombie comedy film Me and My Mates vs the Zombie Apocalypse alongside fellow Australian comedians Jim Jefferies and Alex Williamson.

Fleet is also an accomplished writer, having released Thai Die (2002) and memoir These Things Happen (2015).

“Subtle, Succinct and Surreal” The Scotsman

“exceptionally funny... the audience was spellbound throughout” The Scotsman

“hilarious, hard hitting... hug this man today” The List, Glasgow

“A wild, great show” Herald Sun

“Devilish, menacing and totally mesmerising” The Scotsman

“Greg Fleet is brilliant … inspired nonsense - utterly fresh, utterly hilarious” The Scotsman

“The fastest thinking stand-up around” The Sunday Times, London