Obama and reports blamed a student for the spill, which involved the president's pants and several members of the Secret Service.
But freshman student Kolbi Zerbest blamed the president's "paparazzi" for the spill.
"The Secret Service had asked anyone who was drinking anything, eating anything to place it on the ground or they actually confiscated it from them so that nothing would get thrown at the president," Zerbest told MSNBC's "Morning Joe." She was standing with a group outside The Sink, a popular hangout for students in Boulder.
Zerbest continued, "Paparazzi came up from behind me and kicked the cup" containing what she described as "kind of like a parfait" with fruit and granola.
Following the spill, Obama joked with Zerbest and asked for a napkin.
Zerbest took the blame for the incident, and Obama even referenced her as a "woman [who] got very excited and spilled yogurt on me" in his speech later at the university.
“It wasn’t a lot [of yogurt]," she said. "Honestly, more of it got on me, the ground and on the Secret Service."
Zerbest added that while she only expected to shake Obama's hand, the spill resulted in a few minutes of conversation.
"Getting yogurt on the president, you've got a story to tell," Obama told her at the time, according to the White House press pool report.
"I'm very embarrassed," she replied.
The pool report did not mention "paparazzi."
Obama joked in his speech that yogurting the Secret Service was hazardous. "The agent just stood there looking at her," he said to laughter.
Speaking on NBC's "Today Show," Zerbest denied that the interaction was part of a sorority prank.
When asked if "it was some kind of a challenge" to spill something on "the leader of he free world," Zerbest said, "Oh, my gosh, no, not at all."
"It was a huge coincidence that this happened the same day that I had my initiation, but all in all I would say it was a pretty eventful and memorable day for me," she said.
— This story was updated at 9:50 a.m.