Mark Ealham claimed a season's best championship figures of 6-35 as Northamptonshire, needing 98 to make Kent bat again, capitulated for a second time, totalling a measly 86.
At one stage four wickets fell in the space of six overs until some lusty blows by Paul Taylor, one of only three players to reach double figures, delayed the inevitable before falling to Ealham for 14.
Rob Bailey fell in Julian Thompson's first over and then Russell Warren was trapped lbw next over before David Sales was snapped up by Matthew Walker in the slips. Alec Swann played on to Matthew Fleming while skipper Tony Penberthy drove Thompson straight to Mark Ealham.
Kevin Curran was neatly snapped up in the gully before Toby Bailey and Graeme Swann fell with the score at 66. Ealham then bowled Michael Davies before completing his impressive return having Taylor caught behind.
Kent started out on 59-7 but were indebted to some determined late order resistance to earn a first-innings advantage.
The last three wickets added 126 runs with deputy wicketkeeper Simon Willis and Martin McCague adding 32 for the eighth wicket.
The ECB deputy pitch consultant Peter Eaton watched 17 wickets fall on the opening day but a board spokesman said that they considered the high number of wickets taken were not due to pitch conditions.