Monfort entered his plea Friday in Greeley and was sentenced to two years of probation in a case stemming from his arrest on November 4 in Windsor.
Police say he was pulled over and found to be driving with a breath alcohol concentration level more than three times the legal limit.
During the first six months of his probation, Monfort will have to wear an ankle bracelet that can detect alcohol use and then submit up to two breath tests a day. He also must do 120 hours of community service.
Reports say Monfort has been in alcohol treatment for about two months.