After the first message was played, Te'o said: "It sounds like a girl, doesn't it?"
"It does," Couric responded.
The interview was the All-American's first on camera since his tale of inspired play after the deaths of his grandmother and girlfriend on the same day in September unraveled as a bizarre hoax in an expose by Deadspin.com on Jan. 16.
Te'o's parents appeared with him for part of the interview and backed up his claim that he wasn't involved in the fabrication, saying they, too, had spoken on the phone with a person they believed to be Kekua.
Couric addressed speculation that the tale was concocted by Te'o as a way to cover up his sexual orientation. Asked if he were gay, Te'o said "no" with a laugh. "Far from it. Faaaar from that."
He also said he was "scared" and "didn't know what to do" after receiving a call on Dec. 6 — two days before the Heisman Trophy presentation — from a person who claimed to be his "dead" girlfriend.
The first voicemail, he said, was from what was supposed to be Kekua's first day of chemotherapy for leukemia.
"Hi, I am just letting you know I got here and I'm getting ready for my first session and, um, just want to call you to keep you posted. I miss you. I love you. Bye," the person said.
In the second voicemail, the person was apparently upset by someone else answering Te'o's phone.
The third voicemail was left on Sept. 11, Te'o says, the day he believed Kekua was released from the hospital and the day before she "died."
"Hey babe, I'm just calling to say goodnight," the person on the voicemail said. "I love you. I know that you're probably doing homework or you're with the boys. ... But I just wanted to say I love you and goodnight and I'll be ok tonight. I'll do my best. Um, yeah, so get your rest and I'll talk to you tomorrow. I love you so much, hon. Sweet dreams."
Couric suggested he person who left those messages might have been Ronaiah Tuisasosopo, a 22-year-old man from California, who Te'o said has apologized to him for pulling the hoax.
"Do you think that could have been a man on the other end of the phone?" she asked.
"Well, it didn't sound like a man," Te'o said. "It sounded like a woman. If he somehow made that voice, that's incredible. That's an incredible talent to do that. Especially every single day."
Tuiasosopo has not spoken publicly since news of the hoax broke. The Associated Press has learned that a home in California where Te'o sent flowers to the Kekua family was once a residence of Ronaiah Tuiasosopo and has been in his family for decades.