Krafth denies claims Newcastle players were angered by Isak's antics ahead of his move to Liverpool.
"The media wrote that the locker room would be divided. That's really not true. Football players understand football players and we just have to wish him the best of luck," the 31-year-old told Sportbladet.
"As Anthony ( Elanga ) said, it's been very chill. No one has said or done anything. It's just taken out of thin air. You understand his and the club's situation. Of course, you would have wanted to keep him, he's an incredibly good footballer.
"We were in contact often and talked on the phone. We also met. It's clear that it was tough times for him but he is also mentally strong. It's clear that it was hard for him but he got through it."
But Krafth also understands the anger of Newcastle fans.
"Alex is not just a footballer for me, he is also a close friend. It is clear that you understand both sides – you understand the fans and you understand Alex. It is clear that it has been difficult so in a way it is nice that it is over now," Krafth told SVT Sport.
"Of course it's never fun. Then I think Alex is so mentally strong that he can handle it.
"It's never fun to see scenes where they burn his shirt and make banners and stuff. I don't wish that on anyone."