The 28-year-old was unveiled at Headingley Carnegie on Tuesday morning, taking time out from the Kumuls' World Cup camp to confirm the switch.
Leeds fans will get an early look at the former Cronulla man too, with PNG set to face New Zealand in their final group game at Headingley on Friday.
Aiton joined Wakefield from the Sharks ahead of the 2012 season and has been one of their stand-out players ever since, winning the Player of the Year award in the 2013 Super League campaign.
"I am delighted that we have agreed the deal to bring Paul to Headingley Carnegie," Leeds coach Brian McDermott said.
"He has a wealth of experience both from the NRL and here in Super League with Wakefield and is performing on the highest stage as captain of his country in the World Cup."
Aiton joins Hull's Tom Briscoe and Hunslet's Andy Yates in joining Leeds, with his arrival teeing up the departure of current hooker Paul McShane who has asked to leave.
"I am very happy to be joining the Rhinos," said Aiton, who has transferred for an undisclosed fee.
"I would like to thank everyone connected with Wakefield for making me feel so welcome over the last two years and I am pleased that both clubs have come to an agreement that means I can join Leeds.
"You only need to look at how many of the Rhinos team are in the current England squad to see the quality that is here at the club and I am excited about the future."
Aiton could well make his Leeds debut in a friendly against Wakefield which has been arranged for Boxing Day.
- Sports & Recreation
- Headingley Carnegie