A century from Rob Keogh in a crucial eighth wicket stand with Gareth Berg put Northamptonshire ahead on Day 2.
The pair came together with Northamptonshire stumbling after James Bracey’s hundred had engineered the visitors’ recovery to 223 all out.
Bracey showcased his all-round skills with five dismissals as Gloucestershire reduced their fellow LV= Insurance County Championship Division One newcomers to 129 for seven in reply.
But Keogh, who compiled his 12th first-class ton before falling for 113, shared a partnership of 137 with Berg (66) to guide Northamptonshire to 288 – and there was still time to make inroads second time around, with the West Country side closing on 5 for one, a deficit of 60.
Resuming on 77 not out overnight, Bracey found a capable ally in Naseem Shah – the Pakistan international frustrating Northamptonshire’s bowlers while his partner steered the total towards 200.
Successive boundaries off Ben Sanderson brought Bracey his century and he followed that up with six over long-off, prompting Naseem (19) to start cutting loose at the other end.
A series of productive blows against Keogh extended the ninth-wicket partnership to 80 before the spinner finally got his man, Emilio Gay judging a skier perfectly to take the diving catch at mid-off.
Bracey holed out to Nathan Buck in the next over – but he was soon back in the thick of the action, donning the gloves to take a thin edge from Ricardo Vasconcelos in the third over of Northamptonshire’s reply.
That was the first of a trio of early wickets for Ryan Higgins (4-68), who then collected two in three balls as Ben Curran and Saif Zaib fell to slip catches to leave the home side wobbling at 24 for three.
Gay (18) appeared to have weathered the storm, only to depart on the stroke of lunch and, despite losing a further three wickets in the afternoon, Northamptonshire rattled along at a lively four an over.
Bracey accounted for all three, two of them sharp low catches to dismiss Lewis McManus (15) and Tom Taylor (0).
Berg showed his value with the bat as the veteran all-rounder offered a range of eye-catching strokes, turning the tide as he and Keogh got on top of the bowling and shepherded their side beyond Gloucestershire’s total.
Keogh went to three figures with an all-run four off Higgins and – although a misjudged sweep off Zafar Gohar eventually accounted for Berg – he advanced to 113 before Ben Charlesworth had him caught in the slips.
Gloucestershire 223 (Sanderson 4/66, Berg 2/39) & 5/1 (Sanderson 1/2)
Northamptonshire 288 (Keogh 113, Berg 66)