Mr Justice Norris approved an application by directors at a High Court hearing in London after being told that the npower Championship club owed millions of pounds.
He said he was satisfied that Portsmouth was insolvent and hoped that the appointment of financial experts to manage affairs would allow the club to "stagger on" until a new buyer could be found.
Her Majesty's Revenue & Customs welcomed that decision.
"HMRC is pleased that the court agreed with our view that the creditors of any business have a right to expect that the administrator in these circumstances is completely independent," a statement from HMRC read.
"HMRC felt strongly that the appointment of Hacker Young as administrators to Portsmouth FC, whilst at the same time being administrators for the parent company CSI and its previous roles with the various Portsmouth Football Clubs, would present issues of conflict.
"This is why we suggested the appointment of PKF whose knowledge of the football industry and lack of previous connections to Portsmouth FC should reassure creditors."
With Rangers allegedly owing the tax man £79m, and the likes of Barcelona (one of the world's RICHEST clubs) £500m in debt ... what is the future for football?
All it takes is one of the foreign owners to pull the plug on a Premiership club and the whole thing could have a domino effect.
Celtic reiterated their stance that they do not need Rangers in order to thrive, after First Minister Alex Salmond claimed the Old Firm's fortunes were interlinked.
Celtic statement read: "We are very disappointed with the First Minister's claims that Celtic 'need' Rangers and that Celtic 'can't prosper unless Rangers are there'.
"This is simply not true. In a series of interviews given just three days ago, we made it abundantly clear that Celtic has a well-defined strategy and a business plan independent of the fortunes of any other club.
"That remains absolutely the case.
"The predicament of Rangers is clearly a serious and complex matter with a whole range of possible outcomes.
"However, we are extremely well qualified to make our own position clear and have no wish to see that being misrepresented for political reasons."
St Johnstone manager Steve Lomas: "Scotland needs a strong Old Firm and so it gives me no pleasure to see Glasgow Rangers in the position they're in.
"Hopefully Rangers will sort their problems out and get themselves in a better fitting."
St Mirren manager Danny Lennon feels events at Ibrox should serve as a warning for the rest of Scottish football.
Danny Lennon: "It's very sad for a club the size of Rangers to find themselves in the position that they are in.
"I think it's now time for all the Scottish clubs to ensure they have their house in order.
"Going into debt perhaps will give teams short or medium-term advantage but the current situation shows just how incredibly harmful it can be."