Between devising playoff game plans for the Pats and overseeing an offense that put up 68 points and 839 yards in back-to-back wins over the Broncos and Ravens, he has assembled a coaching staff and tried to keep as many prospective Penn State recruits as possible from running for the hills in the wake of the Jerry Sandusky child sex-abuse scandal.
"Bill has helped me out a ton here," O'Brien said, referring to Patriots coach Bill Belichick. "I have a staff of eight guys in place at Penn State, as well as numerous administrative people who are doing a great job. They're taking care of that end of it.
"This is about the Patriots this week. I'm thrilled to be the head coach at Penn State, but right now, I'm really focused on the Patriots and putting together a great game plan for Sunday and helping us win."
We'll find out later today exactly how much damage the Sandusky scandal and everything that followed, including the firing of Joe Paterno, who died last week, did to Penn State's 2012 recruiting hopes.
O'Brien said he already has a "pretty good idea" of who is signing with the Nittany Lions. One of his assistants will fax him the official list tonight. He'll spend a minute perusing it, then get back to preparing for Sunday's game against the Giants.
"Again, it's more about the Patriots and making sure we're focused on tomorrow's practice, today's meetings, and then on Sunday's game," he said. "After the game, we'll leave for Penn State and we'll go from there."
He disputed suggestions that the Penn State job is one of the toughest in the country right now.
"We feel really good about the staff we have in place," he said. "We feel really good about the team we have in place. I don't view it as the toughest job in the country."
O'Brien, 42, spent 14 years as a college coach before taking a major career gamble in '07 and joining the Patriots as a low-level coaching assistant.
"My wife probably wasn't real happy with me at the time," he said. "It was a little bit of a pay cut [from what he made the year before as the offensive coordinator at Duke].
"But I felt if I wanted to be the coach I wanted to be, I had to work for the best. Obviously, Bill is the best. I didn't feel like it was a step back. I felt it was a chance to go in there and learn and become as good a coach as I could possibly be."
He was promoted to wide receivers coach in '08, spent 2 years as the quarterbacks coach, then was bumped up to offensive coordinator this year, where his unit finished second in the league in total offense and third in scoring.
"Bill shows you the parameters of what he wants," O'Brien said. "And then he lets you go coach, whether you're a position coach or quality-control coach or coordinator. He's a very, very bright guy who demanded a lot of me, and I really thank him for that."
When O'Brien was hired by the Patriots, he said his dream was to be an NFL head coach one day. If he had stayed in New England, there's a good possibility he would have gotten an opportunity somewhere in the next year or two. But then Penn State called and his career path took an unexpected turn.
"You never know when opportunities are going to arise," he said. "When we first started talking about the [Penn State] job, I realized right away what a special place that was. And I felt like I could go in there and have an effect with our staff on some 17-year-old guys. Watch them grow into 22-year-old men and graduate with a great degree. At the end of the day, my wife and I and my family just realized it was an opportunity we couldn't pass up."
Seven years ago, another Patriots offensive coordinator left to take a college head-coaching job. The coordinator was Charlie Weis and the job was Notre Dame.
Weis won three Super Bowl rings with the Patriots and thought all he would have to do was flash those rings and the best high school recruits in the country would come running to South Bend. It didn't quite work out that way. Weis was canned after 5 years.
O'Brien is a little smarter than Weis. He knows that he's going to have to do a lot more than flash a Super Bowl ring or wave his NFL resumé at recruits to get them to come to Penn State. But a win over the Giants certainly won't hurt his recruiting pitch going forward.
"I've had an opportunity to coach for a guy who will go down as one of the greatest coaches in the history of the NFL," O'Brien said. "And I've had an opportunity to coach a quarterback [Tom Brady] who will go down in that regard. Those definitely are things we can take to Penn State and use [as recruiting tools].''
Not to mention an exciting offensive scheme that won't put people to sleep like Paterno's offense.
"Pro football is a lot different than college football," O'Brien said. "But there definitely are certain things that we'll take to Penn State and implement there. And there are things we'll try to put our own stamp on. There's going to be a mixture of some of the things I've learned here and other places, and our own ideas."
Like anyone who has left a job he's loved and a place he's loved, O'Brien has mixed feelings about leaving the Patriots. After Sunday's game, there will be no time for long goodbyes. If the Patriots win, he won't even attend the Duck Boat victory parade down the Charles River. He'll be 400 miles away in his new office on the Penn State campus.
"I love it here," he said. "I love the Patriots. I love these players. I owe a lot to Bill and the Krafts. I've had very meaningful conversations with them over the last 3 weeks.
"There's definitely a part of me that will miss it. I'm from Boston. But the coaching profession, you've got to expect the unexpected. When this game's over, I'll move to Penn State, and that's a special, special place too."