Aidy Boothroyd's fourth signing of the summer is also his fourth in attacking positions with winger Hackett joining fellow wideman Ishmel Demontagnac at the club after the capture of strikers Clive Platt and Alex Nicholls.
Now 29, Hackett was freed by Millwall at the end of last season and had been linked with a return to the SPL, where he played for Hearts, after interest from St Johnstone.
"Chris is a signing I am very pleased to make," said Boothroyd.
"He is someone I have tracked for a while and is another player who has played regularly at a higher level."
Check out Hackett's career stats by clicking below.
http://www.northamptontown-mad.co.uk/millwall/player/career/chris_hackett_8346/index.shtml