Destrehan got off to a 2-0 start in 2011, but the Wildcats faltered from there and didn't get another win the rest of the way.
"This is going to be our year next year," said Marbley (6-0, 215), who played outside linebacker as a sophomore but could move inside this fall.
"I picture myself as an inside linebacker in college," he said. "I'm a smart guy who knows the game. I have great reaction time, and good size and speed. I try to be a very smart player."
The Wildcats welcome four-star WR/DB Rickey Jefferson back for his senior season.
Jefferson's junior campaign was cut short due to an injury.
"Rickey is very important to us," said Marbley. "He's a great player who keeps everybody motivated."
Destrehan has a new head coach with a familiar face: Stephen Robicheaux, who won back-to-back state titles at the school a few years ago.
"It's awesome getting him back," said Marbley of his head coach. "He knows what it takes to have success."