The incident occurred around 11.19pm local time as Frontier Flight 4345, carrying 224 passengers and seven crew members, was departing for Los Angeles.
Airport officials confirmed the pedestrian jumped the perimeter fence and was hit two minutes later while crossing the runway, leading to a brief engine fire and an emergency evacuation.
Twelve people sustained minor injuries during the evacuation, with five requiring hospital treatment, and runway 17L was closed for investigation.
The National Transportation Safety Board (NTSB), Federal Aviation Administration (FAA), and local authorities are investigating the incident.