The final annual report from the Independent Monitoring Board for HMP Birmingham described staff morale as "palpably low" during the process.
After nearly three years, G4S Care and Justice Services took over the prison in October last year.
However, the board has also welcomed the new owner and "looks forward to innovations" that will help the prison.
The Independent Monitoring Board (IMB) was concerned that the privatisation process, with promised announcements, was continually delayed.
It felt that the implementation, from the initial announcement on 31 March to the new owners taking over on 1 October, took too long.
The report praised prison staff who continued to cope with increasing problems, such as gang culture.
During the process, the Prison Service was also bidding to retain the contract and inmates were said to be concerned about the privatisation.
The IMB has recommended that "lessons be learned from HMP Birmingham's experience" and that similar processes should be shortened.
Nine other prisons will go through the market-testing process.
A spokesperson for the Ministry of Justice said: "We will formally respond to the IMB report on HMP Birmingham in due course.
"The public have a right to expect continuing improvement in the quality and efficiency of public services, without compromising public safety.
"The competition strategy and adjustments to the prison estate will help ensure that this is the case, while achieving best value for taxpayers."
A report has highlighted concerns over the process in which a prison became the first in the UK to be privatised.