After taking over from Stuart Gray in a caretaker role, Sampson saw his men suffer three defeats in a row, against Notts County, Rochdale and Shrewsbury before a much-needed win at home to Rotherham.
A few days later, the Cobblers scored twice in the final thirteen minutes to earn a draw against Bradford City at Sixfields, a comeback that convinced chairman David Cardoza to make Sampson his man.
"That is the character and passion that Ian is injecting back into our play," he said.
"The squad Ian has inherited has its weaknesses, and Ian deserves the opportunity, the support and the chance to address them - which he will get in January."