A proposal to make a payment of £1.45million to the struggling npower League One club received unanimous backing from the local authority at a meeting on Wednesday.
The council was satisfied the situation at Pompey had significantly improved since they put the money aside in August 2012.
PST has pledged to pay back the full amount after five months in charge at Fratton Park.
The club's administrators PKF will on Thursday file papers to the High Court to explain how the Trust will fund its bid and the council's loan will form part of that plan.
"This is a victory for the fans and we don't want it to sound like there was any concern about this not being approved," Trust chairman Ashley Brown said, in quotes reported by The News.
"It was a rubber stamping and showed the council is still supportive of us.
"It's now about getting to the High Court and moving the club forward."