Walter Johnson High School hired football assistant Greg Kellner to take over as varsity coach on Thursday, according to athletic director Susan Amos.

Kellner, 30, has worked with the football program for four seasons and headed the junior varsity team in 2013. He joined the Bethesda school as a physical education and health teacher this school year.

The Wildcats went 1-9 this past fall.

“It's always been a dream to be the head coach of a program,” Kellner said. “Being in the program for the last four years, I can see the growth of these kids.”

Kellner replaces Jon Kadi, who stepped down in January after a five-year coaching tenure where the team compiled a 15-35 record. Walter Johnson went 6-4 under Kadi in 2010, its first season above .500 since 1998.

The Wildcats went 14-84 from 1999 to 2008 in the 10 seasons before Kadi took over.

“I just wanted to continue what Jon had started,” Kellner said.

Walter Johnson returns about half the starters from last year's team, Kellner said.

“I'm confident with these guys. I've seen what they can do,” he said. “It's just a matter of going out and executing.”

Kellner has taught physical education and health for eight years, Amos said.

“That plays a big part,” Amos said. “Because I find that if you get a certified teacher, it helps ... you have to be able to teach in order to be a really good coach.”

Kellner was born and raised in Gaithersburg and played football for Quince Orchard, where he graduated in 2001. His father, Eric Kellner, played football for Walter Johnson in the 1960s.

“We've followed football since the days I've played,” Eric said. “... He got the big call. It's exciting.”