Casey clocked in at 3:59.76 in the mile run at the at the MSU Dual Invitational in Worthington Arena.
Casey's time, unadjusted for altitude, marks a first for him as well as the entire state of Montana, as it was the first time any athlete has recorded an unadjusted sub-four minute mile on Montana soil.
With the time adjusted for high altitude, Casey's time marks a current NCAA best of 3:54.59. His stellar performance automatically qualifies him for the NCAA Indoor Track and Field Championships, which will be held March 11-12 in College Station, Texas.
Watch Casey's record-breaking race:
"Pat Casey's time in the mile is just unbelievable," said head coach Dale Kennedy. "To accomplish that here, in Montana, at Montana State, is just a thrill."
Casey finished third at NCAA Championships last year in the mile and will look to remain at the top-spot in the country.
To close out the night, Casey anchored the MSU 4x400 Relay (Nick Melone-Michael Nguyen-Gage Pickering-Casey) that came from behind to win the event with a time of 3:18.73, also a season best for the Bobcats.
It was a strong night for many of Casey's teammates, as well. The Bobcat men defeated Idaho State, 86.5-59.5, and Montana, 86-59. MSU Women's Track and Field was edged out by both Idaho State and Montana, 77-73.
Overall, 47 season-best performance took place at Brick Breeden Field House: 26 for the men and 21 for the women. Most notably, 14 first-place finishes belonged to the Bobcats, with 30 total medal performances on the night.