The England hooker was already contracted for the next two seasons but will now remain at Craven Park until at least the end of 2027.
Litten joined the Robins from Hull FC midway through the 2019 campaign and has gone on to score eight tries in 92 games.
The 25-year-old, who made his England debut in April, has featured 30 times for Rovers this season and scored a try in the Challenge Cup final loss to Leigh Leopards in August.
"I’m buzzing I’ve signed a new deal," said Litten.
"I’ve been here just over three years now and I feel like we’re building as a club. I’m hopeful to be a part of that in the next four years and I’m really excited for it.
"I think we’ve come a long way as a team and it’s showing on the pitch now. But we’re not satisfied with just getting to semi-finals and finals; we want to get there, get that silverware and bring it back for the fans and club."
Head coach Willie Peters has backed Litten to play an important role in KR’s continued development.
"Jez is developing all the time," said Peters. "He’s a popular person within the group.
"The best part for me about Jez is his best is yet to come. There’s no doubt that he’ll be our number nine for the coming years. He’s going to be an important part of what this club does in the future."