Cheseto spent more than two days outdoors after disappearing on Nov. 8, the Anchorage Daily News reported. He is believed to have been running for at least part of the time, with only lightweight clothing for protection in over a foot of snow and single-digit temperatures.
When he reappeared more than 48 hours later in a local hotel, he was covered in snow and could barely speak, hotel staff said. Paramedics were unable to remove his tennis shoes because they were apparently frozen to his feet.
"Damage to his lower extremities was so severe that it required amputation above the ankle on both legs," the UAA Athletics Department said Monday.
Cheseto is expected keep his hands, however.
In a statement, he thanked all those who searched for him during his disappearance, which he put down to "personal issues":
"While I am still recovering - both physically and emotionally - I will do my very best to give back to the community that has helped me so much and to my home country, Kenya. I sincerely apologize for any problems that I may have caused."
Cheseto is believed to have been suffering from depression after his teammate and fellow Kenyan William Ritekwiang committed suicide in February, the BBC said.
Cheseto is expected to return to school next semester to resume his major in nursing and nutrition, according to UAA Athletics Director Steve Cobb.
During his career at UAA, Cheseto became one of the highest-performing athletes in the college's history, the Anchorage Daily News said, setting a local record for the half-marathon and taking several All-American honors. He is one of several Kenyan athletes on the university's successful athletics team.