Pompey made it eight wins from their last 10 matches to stay in the play-off places heading into 2018.
The home side could have taken the lead after just six minutes when Hawkins was played in by Brett Pitman but visiting goalkeeper Matt Ingram was quick off his line to make the save.
Northampton then surprised the hosts when they went ahead in the 36th minute through Chris Long, who calmly slotted the ball past Luke McGee.
But Pompey hit back moments later through Matty Kennedy when he cut in from the left wing to drill a right-footed shot into the bottom corner.
Portsmouth then took the lead on the stroke of half-time when Hawkins headed Christian Burgess’ cross over Ingram’s head.
Hawkins got his second of the match to seal the points, arriving at the back post to nod in a Kennedy cross.
Rangers manager Steven Gerrard is weighing up a move for Liverpool full-back Jon Flanagan, reports claim.
Scottish champions Celtic are reportedly ready to offer full-back Calvin Miller a new deal before sending him out on loan.
Everton target Jack Wilshere has sparked a scramble for his signature after confirming he is leaving Arsenal this summer.
Tottenham's hopes of landing Wilfried Zaha have been hit by the news Crystal Palace have offered him a bumper new deal to stay.
Ryan Giggs says Gareth Bale would be the perfect fit for Manchester United but has doubts over whether he will leave Real Madrid.
Manchester City's attempts to sign Riyad Mahrez could be in doubt again as reports claim Leicester only want a straight cash deal.