Friday's move ends what has been decades of conference instability for USU, which has lurched from the old, defunct Skyline Conference to independent status, the Pacific Coast Athletic Association (now the Big West), independence again, the Sun Belt and the WAC over the past five decades.
The Mountain West, while enduring its own defections (Utah, BYU, TCU, Boise State and San Diego State have either left or are leaving), appears to be an island of stability compared with the WAC which may soon be out of the football business now that it is down to just New Mexico State and Idaho as football members after the latest flurry of departures (Louisiana Tech, Texas State and Texas-San Antonio also have given notice).
The Mountain West will reunite USU with historic rivals Colorado State and Wyoming, as well as Air Force, New Mexico, UNLV and former WAC stablemates Nevada, Hawaii, Fresno State and the Spartans.
The Aggies are expected to be a good fit in the new league. Bringing Utah State won't make up for losing the nationally ranked Broncos and improving Aztecs, but the USU football program is competitive again under fourth-year coach Gary Andersen, and Stew Morrill's men's basketball program has been one of the top mid-majors in the nation in recent years.
Former WAC and new Sun Belt commissioner Karl Benson said Thursday that he couldn't be happier for the Aggies, particularly USU athletic director Scott Barnes and school president Stan Albrecht.
"They have always done things the right way," Benson said. "They were always supportive when they were in the WAC, and they have worked hard to make sure their institution is on solid ground."
Utah State will play this season in the WAC, where both the football and men's basketball programs are expected to challenge for league titles.
Utah State will play Colorado State and UNLV in nonconference football games this season.