Newcastle condemned Saints to a ninth straight league defeat as Matt Burke and Dave Walder led them to victory.
Falcons: (12) 27
Pens: Burke 5, Walder
Drops: May, Walder 2
Saints: (13) 16
The Australian kicked five penalties while Walder landed two drop goals and a penalty to steer the Falcons home.
Saints, who sacked director of rugby Alan Solomons after last week's defeat to Worcester, led 13-12 at half-time after a converted try from John Clarke.
Shane Drahm kicked two penalties and another after the interval, but they remain at the foot of the Premiership.
With Harlequins beating Leeds, Saints are now three points adrift of the rest.
They started well when Drahm kicked an early penalty, but Tom May knocked over a snap drop goal for the Falcons after two powerful drives by Epi Taione.
Burke's opening penalty put Newcastle ahead but Saints got the benefit of a suspiciously forward pass from Bruce Reihana for Clarke to score in the corner.
Two more Drahm penalties, either side of another from Burke, nudged the visitors ahead at half-time.
But the Falcons regained the lead with a Walder drop goal early in the
second half after the Saints made mess of a 22 drop-out.
When Chris Budgeon strayed offside in the 48th minute Burke made it 18-13, but Saints put in a great driving maul to gain a penalty which Drahm slotted.
Burke kicked his fifth penalty before the introduction of Colin Charvis, scorer of four tries for Wales against Japan on Friday, steadied the Falcons.
A forwards drive saw Northampton stray offside and Walder kicked the penalty before landing his second drop goal to seal victory.
Newcastle: Burke; May, Noon, Taione, Stephenson; Walder, Grindal; Isaacson, Long, Ward, Gross, Buist; McCarthy, Harris, Dowson
Replacements: Hurter, Kalman, Sititi, Charvis, Mayerhofler, Charlton, Shaw.
Northampton: Reihana; Human, Stcherbina, Vilk, Clarke; Drahm, Robinson; Budgen, Richmond, Morris; Lord, O'Donoghue; Soden, Blowers, Seely.
Replacements: Van Wyk, Sturgess, Browne, McNamee, Howard, Patston, Rudd.