Instead, the PQ only squeezed into government by less than a handful of seats and her personal victory was overshadowed by a tragic shooting she described as an assassination attempt.
The attack left one man dead and another wounded just metres from the PQ's election night celebration in September.
Marois' rocky first few months have led to more and more questions on exactly how 2013 will play out in the provincial capital.
When will she raise the spectre of another referendum on sovereignty, the PQ's very reason for being? Where will the government retreat next? How long can it last? Will Quebec's students, whom Marois courted leading up to the election, turn on her if they don't like the results of her much-touted summit on education and plunge Quebec back into social unrest?
"We have a lot of work to do," Marois said at her end-of-session news conference, pointing to hearings on a new language law, revisiting the royalties on resource development and creating a provincial economic development bank.
She has already tabled a budget and vowed to tighten spending.
How she handles the economy — and how her government's agenda affects it — will be key to Marois' survival.
With its slim edge in the legislature, the PQ has no chance of passing any legislation calling a referendum during this mandate, something that will no doubt reassure financial markets. Marois has even reconsidered an earlier vow to use public funds to finance studies on independence.
But that doesn't mean the debate won't surface during the year. The PQ's committee on sovereignty is still working and two other parties — the social-democratic Quebec solidaire and the hardline sovereigntist Option nationale — are looking at greater co-operation.
Robert Asselin, a political scientist at the University of Ottawa, says the closer ties between Quebec solidaire and Option nationale pose an interesting dilemma for Marois because they reinforce the reality that sovereignty is no longer the exclusive domain of the PQ.
He noted many harder-line sovereigntists are baby boomers and while they understand Marois is not in the best position to push sovereignty, they'll inevitably become impatient.
"She's squeezed between two camps," Asselin said in an interview. "I think, herself, she's very moderate. She understands that she cannot push this down Quebecers' throats. But there will be a lot of people . . . who will say, 'You're in power, you must try something to make this work. At least pursue a strategy.'
"I think at the beginning of her term it won't be an issue but after a year or so people will say, 'Are you a sovereigntist or not' and people will start putting more pressure on her."
Guy Lachapelle, a Concordia University political scientist, said, however, that sovereigntist hardliners have to be realistic.
"This is a minority government so people will have to be pragmatic and the PQ usually is," he said. Lachapelle said he found the talks between Quebec solidaire and Option nationale intriguing.
"It will be interesting to see how they want to work on the sovereignty question," he said. "They might do the work for Mrs. Marois essentially pushing for that.
"For the sovereigntist forces, they have to work together. Otherwise, they split the vote."
Sovereigntists aren't the only constituency Marois has to keep an eye on.
Quebec students, who saw their anti-tuition increase protest evolve into a grab-bag of rants against a veritable all-you-can-complain-about buffet of social ills, will be sitting down with the government in February for the promised summit on education in the province.
Marois made special efforts to curry the students' favour in the months before the election, wearing their red square emblem and marching in a few protests banging a pot, helping to stoke anger against the Liberals. She even recruited student leader Leo-Bureau Blouin as a candidate.
Marois kept her promise to cancel the unpopular tuition-fee increase but has proposed indexing future increases to inflation.
While students have continued their demonstrations with smaller marches on the 22nd of every month, calm has returned to the streets. It wasn't a complete win for Marois, however, and she noted in a TV interview her support of the students might have cost her a majority government.
Also, the students still want to either pay less or have outright free education.
Adding to the broiling stew of agendas being cooked up for the summit are the concerns of university administrations, who argue that the cancellation of the tuition increase and subsequent demands to trim their budgets to help cut the provincial deficit will leave institutions drastically underfunded.
Marois has ruled out free education but so far the agenda for the summit as well as other consultations leading up to it focus on quality of teaching, accessibility, governance and financing.
Education won't be the only sphere where Marois will be choosing her words carefully in the new year.
During the election campaign, Marois talked tough and promised to pick fights with the federal government to get more powers for Quebec but has said since taking office she'll pick her battles carefully while still representing Quebec's interests.
While Marois trumpeted sovereignty during the election campaign, vowing to call a referendum when the time is right, it has received barely a nod since the PQ took over, apart from the appointment of a minister of sovereigntist governance. The word did not cross her lips at her end-of-session news conference.
What Marois had to talk about, under grilling from reporters, was how much her government had backtracked and fumbled since it took office.
In earlier news conferences, her opponents had lambasted her, with Coalition party Leader Francois Legault comparing her election promises to "science fiction" and saying the government was disconnected from the population.
Interim Liberal Leader Jean-Marc Fournier said her government's record had been marked "by incompetence and shenanigans."
Marois tried to put a happy face on events, saying she had kept her promises, adopting nine of 15 proposed laws.
She pointed to efforts to fight corruption, tighten political spending rules and rein in public finances.
Reporters mainly wanted to know what she had to say about her government's stumbles. She smiled and shrugged, saying she was proud of her government's efforts.
"Nobody is perfect, no government is perfect. But we try to be, we would like to be. But we do our best."
Marois and the PQ ended nine years of Liberal rule in a victory that one columnist dryly noted generated about as much excitement as a kiss from your sister.
It was overshadowed by the attack at a downtown Montreal club where PQ supporters had gathered. In a stunning turn of events, a man fatally shot a sound technician outside the venue and wounded another as Marois took the stage.
Onlookers were taken aback when bodyguards hustled her away from the podium moments after she had promised Anglos their rights would be protected in the aftermath of the bitter and divisive campaign in which identity politics and language had been prominent.
The alleged attacker, who now faces murder charges, yelled as he was being led away that Anglos were awakening.
And in an election where Liberal Leader Jean Charest was highly unpopular and scandal tainted his government, the PQ won 54 seats, compared with the Liberals' 50. The Coalition party took 19 and Quebec solidaire picked up the two others.
The PQ government jumped out to a quick start with nods to its activist base, announcing plans on its first day in office to shut down the province's asbestos and nuclear industries and hinting it might prolong a moratorium on shale-gas exploration indefinitely.
It also promised to abolish a $200 health tax and offset that with retroactive tax hikes on wealthy Quebecers.
But the government's minority status curtailed many of those ambitions.
The health tax remains as a progressive tax that hits people according to income. A new language law was tabled but has less bite than promised during the election. Nothing has really been raised about a proposed charter on secularism.
Longevity? Conventional wisdom is giving the PQ a year to 18 months, mainly because the Liberals won't choose a new leader until March and the fledgling Coalition party is still building its organization. Plus, there isn't really much appetite for a snap election, especially with municipal elections looming in the fall.
While the Liberals were unpopular going into the election and suffered from months of student unrest over tuition hikes as well as allegations of corruption, they ended up being spanked, not slaughtered, when the votes were counted.
"When you only have four seats difference, obviously you're in pretty good shape," said Asselin.
"If Marois doesn't perform well and her government isn't doing well in the polls, then I think with a new leader the Liberals will be in the game."
Asselin cautioned he's not saying they'll win because he believes there are "also a lot of opportunities" for the Coalition party.
"After a year, all bets are off," says Asselin, who adds that once the Liberals get their leader, it all comes down to the best timing for the opposition parties.
"As we've seen in Ottawa, it's difficult for opposition parties to argue for an election before maybe a year into the mandate.
''But if things keep going as they are and it looks like she (Marois) doesn't have a grasp on the government and ministers keep doing gaffes, the economy's not going well — then they'll have an argument to go."