The Railwaymen took the lead in the 16th minute after John Johnson tripped Joel Grant on the edge of the box and Ashley Westwood stepped up to curl the free-kick low around the wall and into the bottom corner of the net.
Cobblers stopper Billy Lumley denied Luke Murphy and his opposite number Steve Phillips somehow kept out Liam Davies's rasping volley before Crewe defender Harry Worley cleared Billy McKay's shot off the line.
Phillips did well to keep out Davies's long-range effort but could not prevent Ryan Gilligan's similar shot finding the net on the stroke of half-time.
The visitors edged ahead 12 minutes after half-time, Adebayo Akinfenwa turning and despatching a side-footed finish into the bottom corner, but Westwood levelled matters in the 65th minute with a low angled finish across Lumley.
And Crewe completed the turnaround when Walton beat Lumley with an unstoppable 30-yard half-volley four minutes later.
Source: Team Talk
Source: Team Talk