For eight years, Tom Allen was the other guy.

First, he was Indiana’s shiny, new defensive coordinator who turned the Hoosiers into the country’s most improved defense. A year later, he was leading the program as its head coach. He stood on the sidelines in Beaver Stadium four times, always wearing red and white colors, always leaving without a win. Starting Tuesday, everything changed.

Allen is now Penn State’s newest defensive coordinator with his hiring made official Tuesday afternoon. He won’t have the opportunity to improve the Nittany Lions’ defense much, but he seems intent on becoming that gleaming assistant coach again. One month after he was fired as the head coach at Indiana, Allen is ready to lead Penn State’s defense.

The turnaround to hire Allen was quick. Fired on November 26 with a healthy buyout, he was first reported as Penn State’s chosen defensive coordinator on Sunday. The switch was even quicker for Penn State, which was only in the market for a new coordinator after Manny Diaz became Duke’s head coach on December 7.

The about-face didn’t seem to matter much to Allen, who spoke to the media Wednesday afternoon. He might not have expected to get a new coaching job as quickly as he did, but he said he was more than ready to pick up the phone when Penn State called.

“You don’t control the clock of the timing of things, you respond, as you do with most things in life,” Allen said. “I’m a football coach, and I just love what I do. This opportunity did present itself and this timeframe was one that I immediately had interest in.”

Allen hasn’t had a lot of time to learn about Penn State’s program, but he doesn’t need much education. His years watching Penn State football from afar, both as a college football fan and as a college football coach, already helped him there.

A former linebacker and a lifetime defensive guru, Allen said he’s long admired what Penn State’s had at those positions. He already knew about the defenses Penn State put on the field, highlighted by some of the nation’s best linebackers.

“I knew it was Linebacker U. I’ve known that for a long, long time,” Allen said. “I love, love that position, and I’m so excited to be able to be a part of a place that’s known for that.”

Allen’s had a whirlwind month. His firing from Indiana came with a hefty payout, which means with a fresh $15.5 million in his pocket, he didn’t have to take a job immediately. Plenty of coaches take time off after losing their jobs, but Allen immediately got back in the game.

Allen was just fired from a better-paying, higher-caliber job as the head coach at a Big Ten school. Still, he appeared thrilled by the prospect of coaching at Penn State.

Allen specifically noted he’s not at Penn State to use the program as a stepping stone to another head coaching job. It’s a stark contrast from Diaz, who came to Penn State fresh off a firing from Miami and immediately said he wanted to be a head coach again. Allen said he came to Penn State for only one reason.

“I’m not coming here for that purpose, I’ll tell you that. I’m coming here as the defensive coordinator,” Allen said. “I’m 53 years old. I’ve had some great opportunities. I am so fired up to be in this position at this place.”

Allen came across as a true football brain. He said he’s not excited to get onto the field, to meet players, or to start playing games. Allen said he just wants to start watching film. The offseason is where he thrives, he said.

“I love this time of year, once we get off the road, and being able to just talk ball,” he said. “I already talked to some DCs about getting together, and I haven’t done that in the last seven years, just meeting places and watching film, sharing ideas.”

Despite his experience as a defensive coordinator, Allen will still have a more interesting transition coming into Penn State. He’ll be watching film of his old Hoosiers teams to break down Penn State footage, not Indiana plays, as he said he did in his interview with Franklin. He’s moving from the head coach at a Big Ten school to the defensive coordinator at a Big Ten East opponent — a switch often awkward for coaches and fans alike.

Still, this opportunity is unique for Allen. He’ll have a chance to work with his most talented defense yet. Penn State may be losing several top players to the NFL Draft, but fundamentals will remain in place with a talented recruiting class inbound. He has at least three starting-caliber linebackers, one of the nation’s best young defensive ends, and rising talent in the secondary.

The knock on Allen has been that he’s never made any of his defenses into the nation’s best. Indiana’s defense was only ever middle of the pack during its best years. Now, Allen will have an excess of wealth to work with.

“You want to go places where the expectations are the standards are high,” Allen said. “I want to be able to build off what they’ve had here.”