Ollie Hannon-Dalby and Keith Barker claimed four wickets apiece as Northants were bowled out for 273.
Youngsters James Kettleborough (71) and Ben Duckett (55) made half-centuries, backed by Adam Rossington (44) and Andrew Hall (43).
Home skipper Varun Chopra was on 43 as the Bears closed on 79-1 from 16 overs.
After the early loss of former captain Ian Westwood, Chopra has so far put on 70 for the second wicket with William Porterfield (24 not out).
After claiming maximum bowling points, the Bears must do the same with the bat on day two to try and close the gap on leaders Yorkshire, who are already in a strong position in their game against Nottinghamshire.
BBC Coventry & Warwickshire's Clive Eakin:
"In truth, Yorkshire's dominance at Trent Bridge is probably good news for Warwickshire.
"The Bears have privately accepted for a while that the title was Yorkshire's to lose but, if the Tykes beat Notts, it puts Warwickshire in a strong position to claim the decent prize money for second.
"Even though they put the bottom county in, this looks a decent pitch. Northants batted well in spells, with Adam Rossington especially pleasing on the eye, but 273 looks below par.
"The short boundary in front of the Eric Hollies Stand encourages brisk scoring and Warwickshire will look to push the game forward on the second day."
BBC Radio Northampton's Chris Egerton:
"Northants began the day learning they are highly likely to miss out on signing Leicestershire's Josh Cobb and they ended it knowing a difficult two days are ahead.
"Despite battling strongly, 273 all out already looks likes being short of a par score and Northants' bowling will need to improve after conceding just short of five an over in the 16 overs possible.
"What is encouraging for Northants' members is that young players such as Adam Rossington (44), Ben Duckett (55) and James Kettleborough (71) are making runs at Division One level.
"Too late to save themselves in 2014 but it gives some optimism for the Division Two campaign next year."
Warwickshire kept their slim County Championship title hopes alive as they enjoyed the better of the first day against Northants at Edgbaston.