Ablett, 28, is approaching 200 appearances for the Rhinos after making his debut 10 years ago.
He said: “I am delighted to have agreed a new long term deal with the club. Leeds is the club I grew up supporting and always wanted to play for.
“We have had some fantastic times in the recent past but the most exciting prospect is what this group can achieve in the future.
“We have got a great group of players for this season and everyone is hungry to get back to major finals and hopefully win more silverware.
“We have had a tough pre-season but everyone is in good shape and ready for Hull KR on Sunday.”
Head Coach Brian McDermott added: “Carl has, over the last few years, steadily progressed into not only a regular starter with Leeds Rhinos but also broken into the international team.
“He has an all round game of high quality attack supported by his sound and efficient defence that can see him play at ease either as a back row or as an attacking three quarter.
“Carl has come through the ranks since joining Leeds as a junior and is just another case of how this great club helps, provides and nurtures home grown talent. Carl has many more years to play yet he can already look back at a hugely successful career and still be even more excited with what’s on offer to him and this team in the next few seasons.
“It’s an exciting time for the current team as over the course of the next few years there’ll be a significant transition of the old guard handing over the task of maintaining succeeds to our new leaders.
“We see Carl as one of these men to lead from the front and continue the clubs philosophies that have been in place for a good few years.”