The A320 flight will operate three times a week, with the potential for more than 1100 passengers each week.
The service was planned in partnership with the Queensland Government and the Fraser Coast Regional Council.
To mark the launch of the new flights, Jetstar has announced a 36-hour flash sale for $59 fares.
Sydney to Hervey Bay is Jetstar’s 20th domestic destination, according to CEO Gareth Evans.
“With international borders closed, our customers are telling us they are keen to explore more of Australia,” he said in a statement.
“Launching in time for the mid-year school holidays, we expect our flights to Hervey Bay will be a really popular holiday option for travellers.”
Hervey Bay is famous for its whale-watching, coral reefs and wilderness.
The new flights were celebrated by Fraser Coast Mayor George Seymour.
“There are not many places in Australia where you can step off a plane after a 90-minute flight from Sydney to a reef, wilderness or whales experience at your doorstep,” Cr Seymour said.
“While the drive market to the Fraser Coast has been strong, we need connections in the sky as well and these new direct flights to and from Sydney will help our region as we continue to emerge from the COVID-19 pandemic.”
Tourism Minister Stirling Hinchliffe said the flights would support 67 jobs in the Hervey Bay region.
Mr Hinchcliffe said the flights had the potential to deliver an $8 million boost to the local economy.