Council members had been asked to reconsider the plan after former leader Russell Goodway "called in" the original decision.
The cricket club borrowed the money nine years ago to finance rebuilding of the SWALEC stadium.
The club's chairman said it faced financial ruin without the deal.
Glamorgan,  which has debts of about £16m, owes around £6.4m to the council for the stadium redevelopment.
In March, councillors agreed to write off £4.4m of the debt - about 70% - to enable the club to safeguard its future.
However, it emerged on Monday that the decision was being challenged by Mr Goodway.
He listed six reasons in a letter requesting the decision be "called in".
These include claims that other options to secure council-taxpayers interest were not considered, concerns about the on-going financial performance of the club and its apparent inability to pay its debts when they fall due.
However, after meeting for three hours on Thursday, the council's policy and performance scrutiny committee rejected calls to refer the matter back to the ruling Labour group cabinet to reconsider.
If followed discussions involving Mr Goodway, officials from the club, representatives of Glamorgan's largest creditors -  Allied Irish Bank - and also from independent financial experts Deloitte.
The final decision means that the deal to write-off the £4.4m by the council will now stand.
Cardiff councillors will not refer the decision to write-off a £4.4m debt owed by Glamorgan County Cricket Club back to the authority's cabinet executive.