A Mira Costa High School graduate who helped lead his Manhattan Beach football team to a championship in 2009 was among the group of elite U.S. Marines killed when their KC-130 Hercules aircraft crashed in western Mississippi this week, family members and friends said Thursday.

Sgt. Chad Elliott Jenson, 25, who grew up in Redondo Beach, where his family still resides, was among the 15 Marines and a Navy sailor who died Monday when the plane went down in a soybean field in Leflore County in the Mississippi Delta. No one survived.

“This kid was a true American and a true patriot,” said Chuck Arrasmith, Jenson’s offensive line coach at Mira Costa. “He was a man for others. He was a man that doesn’t see a ceiling in his life. He just keeps breaking through and achieving more.”

Jenson, who served with the 2nd Raider Battalion, Special Operations Command was based at Camp Lejeune in North Carolina, is survived by his wife of eight months, Jessica, and a stepson, according to his Facebook page and friends.

“It’s unfair — someone so genuine, so selfless. Someone like that didn’t deserve this,” said friend and former teammate Jake Jelmini. “But he was doing something he loved. He was doing something that he stood behind 115 percent.”

Jenson’s family members were unavailable to talk Thursday, but his coach and two teammates remembered a man they described as a “silent leader” who “set the tempo for everybody else to follow,” both in high school and in the military.

“For our high school team, he was the center,” Jelmini said. “He was the guy who set up everybody else on the line.”

Kyle Demarco, Mira Costa’s CIF championship quarterback, said he broke into tears when he learned Jenson had died in the crash.

“He touched so many people’s lives,” Demarco said. “If I have a kid one day, I want him to have the type of character that Chad did.”

Arrasmith spoke proudly of the young man he came to know as a student and remained close to as he served his country, signing up for the military soon after graduation and achieving a spot in the Marine Corps Special Forces Command.

Jenson always contacted his coach when he returned home for visits.

“He’s exactly the kind of person you would want representing the United States in the position that he’s in,” Arrasmith said. “I can’t even imagine a group of people like him being together, how powerful they’d be. They would not see defeat.”

Search teams continued Thursday combing a 5-mile debris field about 100 miles north of Jackson. One of the plane’s engines was located on Wednesday.

The plane disappeared from radar at 20,000 feet while on its way to its first stop in El Centro, California. Witnesses said the aircraft spiraled into the ground, looking like a stunt plane as it went down.

The plane was scheduled to take the Camp Lejeune troops to Yuma, Arizona, for training. The military, along with the FBI and Bureau of Alcohol, Tobacco and Firearms, will conduct an investigation into the cause of the crash.

Word of Jenson’s death spread quickly on social media, including on Mira Costa-related sites and among fellow Marines.

On the Mira Costa varsity football team, Arrasmith said Jenson took over as center as a junior in 2008 when a senior was injured. Jenson was “a good-size kid,” who admittedly wasn’t the most gifted, athletic, fast or coordinated player on the field, Arrasmith said.

But he quickly gained the admiration of his coaches and teammates for his hard work to improve his body and his play.

“He played with a lot of reckless abandon, and the kids loved him for that,” Arrasmith said. “His motor started and it never stopped running. … Chad was just driving down the field, making the block and then he would turn right around and help the running back right up. He was a man for everybody else on the team.”

Demarco said Jenson started as a “goofball type of guy,” but led by example, starting weight-lifting programs and playing summer football to turn himself into one of the best centers in California by the time he was a senior.

“After a play, he would come flying over the pile at full speed. He played through the whistle,” Demarco said. “I think he did that in life, too.”

Telling friends he wanted to serve his country, Jenson signed up for the Marine Corps in 2010. Jelmini said the Marines suited Jenson because he possessed “that cognitive ability to think in a strategic manner, thinking five steps ahead” of those around him.

“Those are the kinds of guys they desire to have,” Jelmini said. “That’s why I think he was so prepared for it. He understood what he was getting himself into. He knew the risks involved, but he was willing to look at those and say ‘I’ll take on this challenge.’ ”

By 2013, Jenson applied for Marine Corps Forces Special Operations Command, a team similar to the Navy SEALs.

On leave, Jenson filled a backpack with bricks, strapped it to his back and ran up and down the stairs at school. Coaches found him in the school’s pool, trying to turn himself into a swimmer.

“He knew going into that that this was going to be an extreme challenge,” Arrasmith said. “There was a lot of swimming and a lot of mountain climbing and foreign languages. … He was on a mission. He knew it would be difficult and he knew there are a limited amount of guys who can make it.”

During the past few years, every time Jenson returned home, his body was more “ripped.” He talked about learning Farsi or taking weapons training or swims in the ocean tethered to seven other Marines.

“Every time you would see Chad Jenson he would have a smile on his face,” his coach said. “He was so proud of his accomplishments and proud to be representing the Marine Corps and the United States of America.”

Demarco said Jenson’s death has left him in disbelief. He looked into Jenson’s eyes before every play on the football field and never imagined “the guy who could climb over any obstacle” would be gone at 25.

“Gone from us way too soon,” he said.