The long, unusual tenure of Clay Helton, the 49-year-old head coach at Southern California, ended Monday afternoon when the school fired him two games into the season. It came more than 11½ years after his arrival as an assistant and almost six after his ascension to the helm. It left an opening at one of the country’s storied football programs.

Donte Williams, an associate head coach who coached USC’s cornerbacks, will serve as interim head coach, his first such turn in a career that has taken him through Nevada, Washington, San Jose State, Arizona, Nebraska and Oregon before his arrival at USC in 2020. He is regarded as an excellent recruiter.

Helton’s head-coaching tenure, long viewed as pretty good but not good enough, ended at 46-24. His 70th game became a flashing-lights loss to Stanford sound-tracked by booing in Los Angeles Memorial Coliseum on Saturday night. Two late USC touchdowns window-dressed the score from 42-13 to a final 42-28, and the Trojans exhibited some of the same issues of football discipline that have plagued them in recent seasons.

Those included nine penalties for 111 yards, and those nine included a targeting call on the opening kickoff and on the kicker himself.

“We’ll see where we are at the end of the year,” Helton told reporters afterward. “And I believe we’re going to be happy at that time.”

The school, which had fired coach Lane Kiffin (nowadays heading Mississippi) famously at an airport in the middle of the night after a trip to Arizona State in 2013 and had fired Steve Sarkisian (nowadays heading Texas) famously in 2015 after he reportedly showed up intoxicated to practice, had its third midseason firing in the past nine seasons.

This one came after a protracted and varied run for Helton, the son of former University of Houston and NFL coach Kim Helton. USC had employed him since winter 2010, through four athletic directors: the end of the tenure of Mike Garrett in 2010, then Pat Haden (2010-16), Lynn Swann (2016-19) and Mike Bohn, who arrived in late 2019 from the University of Cincinnati. Through that time Helton held positions of quarterbacks coach, passing game coordinator, offensive coordinator, interim head coach and head coach.

When Kiffin hired him, Helton had been an offensive coordinator at Memphis and had taken a job two months prior as an offensive coordinator at Arkansas State.

He actually served as interim head coach twice: in 2013 for the Las Vegas Bowl (a 45-20 win over Fresno State) and in 2015 for nine games (a 5-4 record) after Sarkisian’s departure, counting a Holiday Bowl loss to Wisconsin.

His viability after that weighed heavily upon his breakthrough 2016 season, his first full term as head coach. It began at 1-3, but with Sam Darnold at quarterback, the Trojans romped through their last nine games, including a Rose Bowl against Penn State in which USC trailed 49-35 in the fourth quarter but won thrillingly by 52-49.

The next year, with Darnold still at quarterback toward his selection as the third overall pick by the New York Jets in 2018, USC went 11-3 and won the Pac-12 title before losing the Cotton Bowl to Ohio State.

The other years, tucked around those two, cast the most doubt around Helton and sent USC fans into vehemence. Helton went 5-7 in 2018 and 8-5 in 2019 before rebounding to 5-1 in the pandemic-shortened 2020 season. Along the way, he juggled assistant coaches and systems, hoping to right things in 2021, which began with a 30-7 win over San Jose State. It did not help that the former interim coach USC forwent in 2013, Ed Orgeron, won the national championship at 15-0 with LSU in 2019.