"I'm really happy for him that he is living his life the way he wants to live it," she told co-host Matt Lauer. "And that he has found inner peace and just pure happiness. That's what life is about."
"I don't know what life would be like if you always felt like you weren't yourself," said Kardashian, who visited "Today" to chat about her new book. "As long as he is happy, and he wants to live his life, however he wants to live it, that just makes me happy. And I support him 100 percent."
She said there's still an adjustment period for the family members, but she reinforced that the family members are all very close. "Everything takes time," she said. "Bruce wants us to feel as comfortable as possible and take everything at our own pace."
Jenner spoke about his transition during an interview with ABC's Diane Sawyer Friday. During the "20/20" interview, Jenner, 65, publicly declared that he identifies as a woman.
"People look at me differently," Jenner told Sawyer in Friday's interview. "They can see you as this macho male, but my heart and my soul, and everything that I do in life, it is part of me, that female side is part of me. That's who I am."
Jenner said that Kardashian has been "by far the most accepting and the easiest to talk to."