The striker, impressive on loan at Torquay United last season, was recently released by Shrewsbury.
He told BBC Radio Northampton: "They have got a lot of history and are a big club for this level, so as soon as the call came in, I was interested.
"Last season, I found more consistency and I'm looking forward to this being the season I get things right."
Manager Gary Johnson hailed a 'fantastic' signing to add to that of fellow forward Bayo Akinfenwa in what looks already to have the makings of a tasty attacking partnership for next season.