The council was given special dispensation by the secretary of state to increase its council tax beyond the usual level before a referendum must be held in January.
The budget, agreed on Thursday, will target investment into adults’ facilities and children’s home, using an estimated £5.8m extra raised through the increase in council tax.
Putting forward proposals in early February, council leader Matt Golby said raising council tax was “the right thing to do”.
Usually, a council must hold a local referendum on council tax increases above 2.99% annually, but communities secretary James Brokenshire used the local government finance settlement to hand the cash-strapped council a lifeline, allowing Northants to raise council tax by 4.99%.
Golby said: “For the last year it has become customary for the words Northamptonshire County Council to be associated with crisis. That has now changed.
“We have just agreed a budget for next year which balances, and has at its heart a commitment to transform services to make them more cost-effective rather than simply cutting them and responds directly to the concerns people raised with us through the consultation period.
“Of course the budget also includes a 4.99% rise in council tax and we did not take the decision lightly. While not many people welcome a rise in their bills it is important to put this into context.
“For the majority of people in this county it will mean a rise of between 75p and £1 a week. Even with the increase Northamptonshire will be the second lowest charging like-for-like county council in the whole country.”
The council still has a budget gap of £1.4m to make up, but this gap stood at £64.2m in August 2018, after issuing an unprecedented Section 114 notice – banning all non-statutory spending.
A recent survey by the Local Government Information Unit found that 97% of councils are planning to raise council tax for 2019-20.