Kenny Jackett is searching for a player who can give Wolves 'another 10 to 15 per cent in terms of quality'.
Neil Adams says Norwich remain in the market for further additions after signing Cameron Jerome and Carlos Cuellar.
Mantom, 20, has impressed during his second loan spell at the League One club and has now put pen to paper on an 18-month deal.
"I am really pleased that we were able to complete this deal," said Saddlers manager Dean Smith. "Sam is a great acquisition for us. He's a young player who understands the game.
"We know all about him and what he will bring to us; he has hunger and a great attitude to progress.
"He's enjoyed his loan spells here and was keen to commit himself to our cause."