The Kath and Kim star shared the news on her Instagram on Friday, about nine months on from being diagnosed with stage-four mantle cell lymphoma, described as a "rare and fast-moving blood cancer".
"I wanted to share the fantastic news, which is I've completed chemo and I am now in remission - so phew, big relief," Szubanski said on Instagram.
"It's not a cure, but because I got a good remission, that hopefully means I'll keep the cancer at bay for a good long time."
Best known for winning the hearts of Australians as the sporty, unlucky-in-love Sharon Strzelecki in sitcom Kath and Kim, Szubanski said she was "eternally grateful" to her medical team and public well-wishers.
She sported short hair that had regrown since she had shaved her head to prepare for the treatment in May.
Her portrayal of Sharon sparked character roles in smash-hit movies including Babe and Happy Feet.
She first burst onto Australian screens in the mid-1980s after being picked up by ABC talent scouts watching her perform in a university revue.
Her credits also include sketch shows Fast Forward and critically acclaimed Big Girl's Blouse, alongside Kath and Kim co-writers Gina Riley and Jane Turner.
Szubanski, a staunch LGBTQI rights activist, began her announcement by wishing followers a happy Mardi Gras.
The Glitter Club - described as a premium vantage point for the Mardi Gras parade in Sydney's Taylor Square - has been rebranded Magda's Glitter Club for Saturday's marquee event.
"I am so gutted I can't be there. I'm afraid it's unavoidable, but have a wonderful time and big love to you all," she said.
In 2018, she was appointed an Officer of the Order of Australia for her contribution to the marriage equality campaign.
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