Matt McGloin was a fifth-year senior. Christian Hackenberg was a true freshman.

They were the Penn State quarterbacks in Bill O’Brien’s two years as head coach of the Nittany Lions a decade ago.

On Friday, Ohio State hired O’Brien as offensive coordinator and quarterbacks coach to lend an experienced hand to an offense that underperformed last year.

McGloin’s and Hackenberg’s experiences provide a strong clue as to what to expect from O’Brien with the Buckeyes. O’Brien called the plays for Penn State and worked closely with the quarterbacks, as Ryan Day did in his first five years as OSU coach.

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O’Brien took over at Penn State at the lowest point in the program’s history. The Jerry Sandusky sex-abuse scandal broke in late 2011. Legendary coach Joe Paterno was fired.

Months after O’Brien’s hiring, the NCAA leveled sanctions against Penn State that many expected to decimate the program for years. In the pre-transfer portal era, the NCAA allowed PSU players were free to leave and be instantly eligible elsewhere, and many did depart.

But O’Brien held enough of the core of the team together.

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“I remember him saying, 'We're nobody's charity case,’ ” McGloin said. “One of those things he mentioned was, ‘You can leave if you want, but if you stay you'll be remembered forever.’ We just slowly came together as a team, and he led every step of the way.”

Penn State went 8-4 and O’Brien was named the Big Ten’s Coach of the Year.

O’Brien isn’t in charge of the entire program at Ohio State. But like Jim Knowles with the defense, O’Brien is expected to have considerable autonomy over the offense.

Both McGloin and Hackenberg said the Buckeyes will be in good hands with him.

“I'm probably the biggest fan of Bill O'Brien that there is,” McGloin said. “This is somebody who loves football, is passionate about the game, who is extremely fair to his players.

“He’s very demanding on a daily basis, expects the best out of you, but will always support you and will always have your back and truly believes in that team atmosphere.”

Hackenberg also raved about O’Brien.

“I have nothing but great things to say about him,” he said. “He coached the hell out of me. I loved how hard he was on me, and I love how much he expected and how much he put into me.”

McGloin started his career as a walk-on and became a part-time starter for two seasons before becoming the full-time starter under O’Brien. Paterno’s offense was hardly cutting edge, and O’Brien came from the New England Patriots and quarterback Tom Brady.

McGloin said he would spend hours standing in front of the mirror just to learn the verbiage of the complex scheme.

“There was a massive, massive learning curve for me because I had never done anything like that in terms of an offensive system,” he said. “But we just grinded. Every day, we just attacked it. We knew how difficult it was. But Bill was looking for people to step up. Everybody was looking for leaders to step up. He found a way to make guys embrace their roles, not just accept them.”

O’Brien is a fiery New Englander, and he didn’t sugarcoat his words.

“I got yelled at every day, I think,” McGloin said with a laugh. “But it was fun. It was challenging. It kept me on my toes.

“He completely broke us down as an offense and completely broke me down as a quarterback and then built it back up.”

O’Brien demanded that his quarterbacks know every aspect of the offense in great detail. But once they did, McGloin and Hackenberg said, he gave them authority to change play calls at the line of scrimmage.

“I think early on I got the impression that he was going to put his trust in you,” McGloin said. “When you have a coach who hands you the keys to the car and says, ‘Go ahead,’ that’s very motivating.

“With Bill’s leadership capabilities, the way he understands the game and sees the game, you have the answers before you take the test. That’s what you need out of a coach.”

McGloin and Hackenberg said O’Brien ran the Patriots’ scheme, but he adapted to his personnel. McGloin was more of a gritty, dual-threat quarterback. Hackenberg was more of a pocket passer.

“He’s not a square-peg-into-a-round-hole guy, that’s for sure,” Hackenberg said. “He's going to have some things that are consistent within his schemes that he believes in, but I do think he's going to try to put those guys in the best situation to be successful.”

Added McGloin, “He's one of those coaches where if you're not comfortable with it, he's not going to call the play. I've had coaches who don't care if you like the play or not. They're still going to call it because they want to call it. Bill's not like that.”

Under O’Brien, McGloin threw for 3,271 yards with 24 touchdowns and nine interceptions and a completion percentage of 60.5. The previous two years, he threw for 3,119 yards and 22 touchdowns, but with 14 interceptions and a completion percentage six points lower.

He went on to play from 2013-18 in the NFL.

“It would not have happened without Bill O’Brien,” McGloin said. “I’m absolutely confident in saying that I wouldn’t even have gotten my foot in the door without Bill.”

Hackenberg was a five-star recruit when he succeeded McGloin. But the learning curve was steep, especially since he enrolled after spring practice.

“I was just young and dumb going in there,” Hackenberg said. “I knew I had a chance to compete for the job, and Bill gave me all the resources I needed to learn what I needed to do to gain his trust.”

But it wasn’t easy.

“I was doing 400-level classes as an 18-year-old,” he said. “I was literally trying to make checks and going through stuff like Tom Brady was doing in meetings. I’m not saying I was at that level, but those were the expectations, and he gave me the keys and let me drive the car.”

Hackenberg played only one season for O’Brien, who left after the 2013 season to become coach of the Houston Texans. Hackenberg’s freshman season was by some measures the best of his three-year college career.

He threw for a career-high 20 touchdowns and had his best completion percentage (58.9) that year before James Franklin took over the program and implemented a simpler offense.

“I almost went from like doing astrophysics to going into your intro 100-level courses,” Hackenberg said. “That was like the biggest shock for me in my career. It was nothing that coach Franklin did wrong. I’m just saying I think that autonomy (under O’Brien) is unheard of, especially for an 18-year-old kid.”

Hackenberg left Penn State after his junior year. The New York Jets picked him in the second round of the 2016 draft.

O’Brien has had success and failure since leaving Penn State. Last year, as the Patriots’ offensive coordinator, New England tied the Carolina Panthers for the lowest-scoring offense in the NFL. In fairness to O’Brien, the talent on the Patriots’ offense was considered among the worst in the league.

With Ohio State, O’Brien will work with a significant talent advantage in most games.

“I think the sky’s the limit,” McGloin said. “I don’t want to speak for Bill, but I’d have to say he’s pretty excited.”

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This article originally appeared on The Columbus Dispatch: O'Brien's Penn State QBs rave about new OSU offensive coordinator