International rating agency Standard and Poor's has awarded the territory's economy the highest possible AAA credit rating.
The agency expects the ACT economy to remain consistent with the top rating for the next two years.
ACT Chief Minister Andrew Barr welcomed the rating, saying it was a strong endorsement of the government's economic and fiscal management record.
"According to Standard and Poor's, the rating reflects 'the territory's very strong economy and financial management, strong budgetary flexibility and exceptional liquidity'," he said.
Mr Barr said the agency considered the ACT financial management to be strong, despite noting the impact of the Asbestos Eradication Scheme on the budget.
The government's buyback scheme was financed by a $1 billion Commonwealth loan, with Standard and Poor's saying the budget would strengthen as the scheme progressed and homes were resold.
The budget also included funding to pay for the $783 million tram project, but the government plans to sign up a private partner to deliver the project, paying the consortium a lump sum of about $375 million around 2019, then an annual fee after that.
Debt has increased sharply in the past two years, as the government borrows for its big-picture infrastructure program and to pay for the Mr Fluffy buyback and demolition program.
Net debt was just $500 million in 2013-14, jumping to $1.35 billion in 2014-15, and $2.23 billion in the 2015-16 budget delivered earlier this week.
"In our view, the institutional framework promotes a strong management culture and fiscal discipline across Australian jurisdictions," the Standard and Poor's statement said.
"The ACT's debt and liquidity management and its management of government-related entities support our view."
Mr Barr said the government remained committed to supporting jobs during the Commonwealth's cuts to employment and spending, by investing in infrastructure projects.
"Standard and Poor's also noted the ongoing improvement in the stability of the ACT's own-source revenue as a result of tax reform," he said.
Earlier this month, Mr Barr said the economy had turned the corner after the Australian Bureau of Statistics found growth measured by state final demand had increased by 3.1 per cent during the June quarter.
Canberra Business Chamber chief executive Robyn Hendry agreed the economy had proved resilient in the past few years, despite remaining concerned about rising debt.
"There is other evidence to say this is true, including signs of increasing consumer confidence like retail figures," she said. "Clearly the market is telling us the worst is over."
Ms Hendry said the private sector had provided jobs to retrenched public servants, but more time was needed to judge its ultimate success.
"Private sector investment is down although it does take a while for those investments to materialise and you are not going to get them coming through immediately," she said.