McManus, 27, has been on loan at the Northants since the start of the season, following the sudden departure of former captain and wicketkeeper Adam Rossington. He has been a mainstay in the first XI, playing every game so far in the Championship and Vitality Blast.
“I am delighted to have signed for Northamptonshire on a permanent basis.” McManus said. “I have loved my time here so far this season and it is a great club. I am thoroughly enjoying playing with the boys and working with the coaching staff.
“I’m really excited for the next two years with Northamptonshire and to see where we can go and challenge for silverware.”
McManus averages 29.28 with four half-centuries in the championship, sitting mid-table in Northamptonshire Division One. On the Sunday before the start of the Royal London One-Day Cup, he scored a century in the practice match against Bedfordshire.
“He has been brilliant, an absolute true professional, a top man and one hell of a cricketer,” said Northamptonshire head coach John Sadler. “The boys have a lot of respect for him and he is going to play a big part for us going forward.
“He’s an open-minded character who wants to learn, and constantly improve. We know how good he is, and we know he just keeps getting better”.
“Coming into a new dressing room can be difficult to be assertive. But he has grown and settled as he is, and since it was announced that he would be here for the entire season he was behind the sticks. Has become a natural leader. We can’t blame him, and we are happy to have him on board.”
McManus entered Hampshire in 2015, making his first-class debut, but with the arrival of Ben Brown from Sussex his prospects for first-team cricket were cut short.
Hampshire’s Director of Cricket, Giles White, said: “Lewis has been a wonderful servant to the club and an incredibly popular player. We will miss him. On behalf of everyone in Hampshire I want to thank him for his contributions over the years .and best wishes to him on visiting Northamptonshire.”