In a political career that spanned more than 30 years, Marois held various cabinet positions before becoming premier in 2012 with a minority Parti Quebecois government.
Her stewardship of the province as Quebec's first female premier would last just 18 months.
On Wednesday, she met with incoming premier Philippe Couillard, whose Liberals romped to victory in last week's election with 70 of the province's 125 seats.
The PQ was relegated to just 30 seats, prompting Marois to announce her political curtain call that night. Officially, she will remain PQ leader until a party meeting in early June when Stephane Bedard takes over.
The outgoing premier said she was very proud of her government's accomplishments.
She said she was able to control government expenses, improve Quebec's economy and defend the province's interests over the last 18 months.
An emotional Marois had to wipe away tears and ask someone for a tissue as she read a statement and answered questions after her private meeting with Couillard.
"It'll soon be seven years that I left my garden, after a short retirement, because I still wanted to serve Quebec," she said.
"Since then, a lot has happened and, I think you know as well as I do, that it wasn't all smooth sailing. But I don't regret anything."
Asked about the state of the sovereigntist movement, Marois said there will always be Quebecers fighting for a country.
"I think this project (sovereignty) is always an important necessary project for our nation and I am sure many leaders, many citizens will continue to fight to be a country one today. I don't know when. I don't know how.
"But one thing I know is that we (would) be in the best situation if we were independent. I am sure of that. We are different. We are a nation."
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