Earnings last year had been hammered by the impact of a £108.9 million settlement after it emerged the group overcharged taxpayers for the electronic tagging of offenders, as well as by costly restructuring.
But pre-tax profits for the first half of 2014 were £85m, up from a £94m loss for the same period the year before.
They were also up 12 per cent on an underlying basis -stripping out one-off charges for the previous period - to £124m.
Chief executive Ashley Almanza, who took over from Nick Buckles last summer following the emergence of the tagging scandal, said G4S had made good progress in the first half.
He said the group had won new contracts with a total value of £1.2 billion. But he added: "There remains much to be done to capture the full potential of our strategy and to strengthen the group's performance."
G4S reported a pre-tax loss for 2013 of £186m and had been banned from bidding for Government contracts until April when the embargo was lifted following its settlement over the tagging scandal.
The company's UK and Ireland revenues for the first half of this year were down two per cent to £790m as a result of the loss of the tagging contract, offset by improved performance from its cash transit operations. Group revenue climbed four per cent to £3.37bn.