This is an unfamiliar playbook for Carson Palmer.

Sure, he has the NFL pedigree and the Heisman Trophy, and a staff of assistant coaches loaded with pro experience. But he’s the first-year coach at Santa Margarita Catholic High School, his alma mater, and stepping into an elite league of schools while studying not just game tape but reels of red tape.

“This is harder than I thought,” said Palmer, 45, sitting in his office above the practice field. “Year One is tough. The NFL is fast and responsive. Here, changing the playbook software takes an act of Congress. But I’m learning every day.”

Not that he’s complaining. He knew when he took the job eight months ago that his path would be littered with challenges and obstacles. Along with some satisfying successes.

The Heisman Trophy winner and former No. 1 overall pick has spent his adult life in that wafer-thin line at the top, the lofty latitude occupied by the best players in the game. Now, he’s getting back to basics.

“I enjoy seeing a kid make a mistake, then understand the why and fix it,” he said. “You don’t get that in the NFL. There, it’s just a job. Here, there’s joy in learning.”

The Eagles, ranked No. 7 in the Southland by The Times, open their season Friday against No. 6 Mission Viejo.

Said Palmer, engrossed in preparing the program for the last eight months: “It’s time.”

Santa Margarita coach Carson Palmer watches over practice on Wednesday.

(Allen J. Schaben / Los Angeles Times)

He will have his hands full in the Trinity League, easily among the most competitive leagues in the country and featuring football powerhouses such as Mater Dei and St. John Bosco.

Are those opposing coaches looking for their Carson Palmer pelt on the wall?

“It’s not about the coach,” Palmer said. “Programs where the coach is the focal point don’t work. It’s about the players 100% of the time. I can help them because I was taught by great minds, but I’m just passing it on.”

Santa Margarita has standouts in brothers Trent and Grant Mosely, both wideouts and Trent committed to play at USC. At quarterback is Trace Johnson, who played high school football in Florida before transferring to spend his senior season with Palmer. His father, Doug Johnson, is Santa Margarita’s quarterbacks coach and played the position in the NFL.

Cornerback Jayden Crowder is heading to California, safety Logan Hirou to UCLA. Dash Fifita, a first-team All-Trinity League linebacker last season and nephew of Santa Margarita’s defensive coordinator, is committed to Arizona, and fellow linebacker Leki Holani is going to Sacramento State.

Santa Margarita coach Carson Palmer instructs his players during practice.

(Allen J. Schaben / Los Angeles Times)

Palmer has several assistant coaches with NFL and/or major college football experience, among them running backs coach Mike Karney, a bruising fixture at fullback for the New Orleans Saints; receivers coach T.J. Houshmandzadeh, one of Palmer’s standout targets with the Cincinnati Bengals; offensive line coach Lenny Vandermade, among Palmer’s blockers at USC; defensive coordinator Steve Fifita, a standout at the University of Utah who later played in the NFL; and linebackers coach Rob Thomas, who was Pac-10 defensive player of the year as a UCLA linebacker and played eight NFL seasons with four teams.

“It’s been awesome,” Karney said. “Carson’s been running the program the way it should be run but putting his own twist on it, making it his own. From how we run practice to what we’re doing schematically, there’s a lot of carryover from the NFL.”

Palmer said it isn’t necessary to have a staff with so much playing experience, but it’s helpful.

“These guys know the importance of staff chemistry,” he said. “I’ve heard high school coaches say the hardest part isn’t the kids or the parents, it’s the adults and their egos. That’s why I was intentional about picking guys who get along. No one’s doing this for the money.”

Before accepting the job, Carson frequently consulted with Pete Carroll, his legendary coach at USC who is now leading the Las Vegas Raiders.

Carroll believes Palmer will be successful in this endeavor, but that it will take time.

Santa Margarita coach Carson Palmer instructs a player during practice.

(Allen J. Schaben / Los Angeles Times)

“He’s going to take his knocks, I’m sure,” Carroll said. “He’ll have first- and second-year issues like all the coaches do — just getting your act together and trying to figure yourself out.

“We went extensively into that when we got together — helping him understand some of the questions that will be raised: What am I standing for? How hard am I? How tough am I? How open am I? All of those kinds of things that come into coaching.

“He’s tough, he’s demanding, and he has high expectations for anybody that plays — just like he held himself to all those years. I think he’ll do a wonderful job. He has a great love for the school and the setting, and he was really excited about the opportunity to go back. He’ll put his best foot forward, but it’s a challenge now. He’s got good guys working with him, too, so that’ll all help out. He’s going to do just fine.”

Palmer said he frequently gets phone calls from Norm Chow, his offensive coordinator at USC, who delivers a simple and powerful message.

“He keeps calling me and saying, ‘Culture before Xs and O’s,’ then hanging up,” Palmer said. “That sticks with me. It doesn’t matter what you run. It’s, do they believe in it? Do they trust each other? Is there an environment for growth? We don’t haze. We respect each other.”

That meant showing some players the door.

“Some kids didn’t fit culturally with what I envisioned,” he said. “This is the Trinity League. It’s big-boy ball.”

Santa Margarita coach Carson Palmer speaks to his players during practice on Wednesday.

(Allen J. Schaben / Los Angeles Times)

And that also means coaching some sophisticated concepts, which he said his players are grasping to a surprising degree.

“I’m just giving them what I was given,” he said. “I use Bruce Arians’ short passing game, Norm Chow’s trick plays, the play-action stuff of [Steve] Sarkisian and [Lane] Kiffin.”

He borrowed, too, from Greg Knapp, the longtime NFL offensive coordinator who died in 2021 after a bicycle accident.

“Greg was a master installer,” said Palmer, who played for him in Oakland in 2012. “He’d give surprise quizzes in the meeting room to keep you awake. ‘What’s the capital of Nevada?’ I do that now. Meetings aren’t sit and stare. We’re on the move.”

How will that translate in terms of wins and losses? We’ll see. One of his old and beloved coaches is optimistic.

“The respect for him is automatic, right?” Chow said. “Just because of who he is. … When you’re coaching, you need to be able to run the room. With Carson, young people say, ‘OK, I’m going to listen.’”

Then, perhaps the highest praise.

“I’d absolutely want my kid to be coached by him,” Chow said. “Because of the human being that he is.”