Passage of the budget, by a vote of 64 to 36 with only the Tories opposed, was a major achievement for rookie Premier Kathleen Wynne, who took over as leader of the Liberal party from Dalton McGuinty in February.
"I won't deny that I am relieved that we are here," Wynne told reporters after the budget vote.
"I think that the work that we have done over the past few months has borne fruit, and is in direct response to what people have said to us about making the minority legislature work."
The NDP has been very critical of the government for the mass deletion of emails pertaining to the cancelling of gas plants in Oakville and Mississauga, but said they had secured enough changes in the budget to support the Liberal fiscal plan.
The budget includes NDP proposals for a youth jobs' program, a cut in auto insurance premiums, an increase in welfare rates, more money for homecare services and the creation of a new Financial Accountability Officer to help avoid future scandals.
"You can scream blue murder or you can actually roll up your sleeves and try to make change, and that's what New Democrats have done with the Financial Accountability Office," said NDP Leader Andrea Horwath.
"This measure is needed to stop scandals like the ones that occurred under their watch, like eHealth, like Ornge, like the gas plant scandal, from ever happening again."
The Progressive Conservatives took themselves out of the picture by saying they'd vote against the budget even before they read it, added Horwath.
"Unlike some others in this House, we are actually working hard to get some real results and some real accountability for the people who elected us," she said.
"Unfortunately the Conservatives have been more interested in their own political antics and games, but for us it's more serious than that."
Wynne said it was "surprising" the Tories didn't try to make some changes in the budget like the NDP did.
"There are initiatives in this budget that actually speak to some of the concerns of the Progressive Conservatives," she said.
"The issue around the employer health tax, which speaks to payroll taxes for small businesses and relief from those, that's an issue I would have thought would have been supported by the Conservatives."
PC Leader Tim Hudak made one last appeal to the NDP before the vote to help the Tories defeat the budget and force a summer election.
"I want to send a message to the NDP that there is a choice before them today ... a choice to prop up a corrupt government that has been part of not only one, but two OPP investigations," said Hudak.
Both the Tories and NDP have accused the Liberals of destroying the emails to cover up the cost of cancelling the gas plants, which has soared to $585 million, far above the $230 million the government had been claiming.
The Ontario Provincial Police last week announced a criminal investigation into the wiping out of email accounts. The OPP was already investigating allegations of financial wrongdoing at Ornge, the province's troubled air ambulance service.
Hudak lashed out at Horwath for supporting the Liberal budget.
"Premier, you're going to thank the leader of the NDP," said Hudak. "She's tied herself into a human pretzel just to prop up a corrupt government."
Outside the legislature, Horwath joked about "sticks and stones," defended her decision to work with the Liberals to get changes in the budget, and lashed out at the Tories for saying they'd vote against the fiscal plan before they even read it.
"Mr. Hudak can call all the names he likes, and he can scream from the rooftops, but what has he achieved," asked Horwath. "I don't think he's achieved anything for the people of Ontario, but I think New Democrats have."
Horwath warned an election now would kill the justice committee hearings into the cancellations of the gas plants, which the opposition parties say were killed to save Liberal seats in the 2011 election when they were reduced to a minority government.
Wynne said the public expects the three parties to co-operate in the minority parliament, and praised Horwath for working with the Liberals to make some key changes to the budget.
"She brought forward the idea of the Financial Accountability Officer ... a good idea and something that we can act on," said Wynne.
The legislature adjourned until Sept. 9 following the passage of the budget.