The 34-year-old hooker is in his 17th season of Super League, having begun his professional career with Wigan in 1997, and also had spells with London Broncos and Warrington before joining the Vikings ahead of their return to the top flight two years ago.
"I'm delighted to extend my contract for another 12 months and equally as pleased that my body is allowing me to prolong my career and carry on playing with the Vikings," Clarke said.
"Over the next couple of seasons, Widnes are going to be right up there challenging for honours. It's exciting to be a part of that."
Widnes coach Denis Betts said: "Jon has been our best player by far all season and he is leading the team around really well and offers us so much on the field.
"He is healthy, strong, experienced and one of the fittest blokes at the club and, regardless of his age, he still wants to play the game which is great news because I want him to carry on playing too."
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