"Our defensive staff of [Kevin] Steele, [Chris] Rumph and [Dan] Brooks, I love working with those guys," he said. "You just don't want to leave something like that. At my age in my career, I love it."
Of course, it also helps Harbison's secondary was downright salty in 2009.
The Tigers gave up only 163 yards per game, seventh-best in the NCAA and best in the Atlantic Coast Conference. Clemson's pass efficiency defense was also 21st in the country and third in the conference.
Plenty of experience is back in 2010, too.
Safeties DeAndre McDaniel and Rashard Hall return after combining for 14 interceptions in 2009. The most versatile component, Marcus Gilchrist, is starting at cornerback along with Byron Maxwell. Xavier Brewer is also in the mix as a standout performer so far during camp.
Harbison said after Tuesday's scrimmage he would like for this year's unit to develop its own identity.
"Last year's team is last year's team. This team has to get its own personality," he said. "What we have to do right now is take care of it one down at a time. Once that happens during the game, we'll see where we are at the end of the season.
"Right now, we can't look at that. We have to play one down and one quarter at a time."
Harbison is also determined to stay on top of his players, even with so many veterans returning.
"You have to coach them even harder because you can't let them relax. You have to keep coaching them like it's their first time here," he said.
Freshman Bashaud Breeland's name has bounced around during interviews with veteran players.
"He's got a ways to go," he said. "In this system, you have to play with your eyes. You have to see the system, make your checks. Talent-wise, he's got the talent. Mentally, he's got a ways to go."
Seven days of practice are now in the books, including Tuesday morning's stadium scrimmage—the first of three this preseason and so far Harbison and his group appear to be on track.
The defensive backs were mentioned by Dabo Swinney as the top unit on the field late last week and the stats from Tuesday's scrimmage reveal a solid performance.
On the day the Clemson offense racked up 185 yards through the air and completed just 16-of-36 passes (44 percent).
The first and second team defenses also didn't give up any touchdowns through the air.
But don't tell that to Harbison, aka Coach Cheese.
"We've got a lot of work to do," he said. "They played good in spurts. We have to be consistent and play with our eyes more," Harbison said. "I have to watch the tape. There are some plays that we gave up. But at times it seemed like we executed pretty good. There are some things, I think, we shouldn't have given up."