The hosts were determined to cash in on bowling Lancashire out for 123 in their first innings and with Murray Goodwin on 44 not out they eased to 203 for eight.
Stephen Peters, with an unbeaten 43, steadied the ship for Northamptonshire after Kyle Coetzer was trapped lbw for six by Mark Davies in the seventh over as the visitors chased Kent's first innings total of 271.
Northamptonshire had progressed to 77 for two at lunch, trailing by 194 runs.
Meanwhile, Ned Eckersley scored 45 as Leicestershire reached 96 for four in their second innings, 66 runs ahead with six wickets remaining on the third day of their match against Gloucestershire at Grace Road.
- Sports & Recreation
- Murray Goodwin
- Kyle Coetzer
- Stephen Peters