The Wales winger has penned a new contract to 2029.
James moved to Leeds from Manchester United in 2021 and has gone onto make 120 appearances.
“I’m obviously very pleased, it's a massive day for me and my family,” he told LUTV.
“I'm glad it's been done so early in pre-season and it's nice to just settle now and yeah, I am just excited for the future.
“So I am absolutely delighted to extend my contract here, it definitely feels like home. It's an amazing club and I can't wait for the coming years. I've got a lot to give as a player and hopeful we'll go on to bigger things.”
Weird to be a senior pro
Now 27, James also said: “It feels strange for me to say that I'm a senior pro because I still feel really young. I think people still think I'm 18!
“So yeah, it does feel weird, but you do take a lot more responsibility. I think naturally I try to take more responsibility out on the pitch now.
“I let the people who want to do the talking in the changing room, then I kind of try to lead by example on the pitch. But I think being a more senior player now, I have to give that experience to the players.”