His execution has helped elevate a part of Boyle's game that was believed to be a weak link before the season.
"He's done an outstanding job," said Chris Mason, the assistant coach responsible for Boyle's line play. "He's been able to step up and provide great leadership."
Arnold said the jury will remain out on that until after Boyle's game Saturday against Highlands in the Class AAA championship in Louisville.
"To this point, I think my leadership has been really good," he said. "After the (first) Highlands game, I think (it) improved a lot, especially the last three or four weeks."
It starts with him playing well
Leadership means different things to different people, and Arnold said to him it starts with making sure he's playing as well as he can play.
"For me, leading by example gets the point across a lot better than talking to somebody," he said. "I think that has a bigger impact on younger players than anything else.
"In practice, when everything starts clicking and everybody's on the same page, that's when you know the leadership is good. You just feel it."
Arnold said he was motivated by the buzz before the season that Boyle's lines might be the weakest part of its game.
"It motivated all of us, those seniors especially," Mason said. "This is their last go-around, and those linemen wanted to show them they're not the weak link."
Arnold showed that in the Rebels' semifinal win over Hopkinsville, when Mason estimated that he had "five or six" pancake blocks (that put an opponent on the ground).
"That's always good," Arnold said.
Pancakes are one of the few tangible statistics by which offensive linemen can measure their play. But Arnold said another good gauge is the rushing yardage racked up by Quinn Givhan and the Rebels' running game.
"If Quinn's got good rushing yards and we're able to move the ball, that's a little more impressive to me than the actual score," Arnold said.
By the same token, his first priority on defense is stopping the run. But he said Boyle's defense must also focus on stopping the big plays the Rebels gave up in their 21-0 loss to Highlands on Sept. 17.
"We'd get them third-and-10 or third-and-15 and they'd break a 60-yard run. That shouldn't happen," he said. "We've got to stop the run and stop the big plays."
Arnold, who is first on the team in fumble recoveries (three), second in solo tackles (68) and third in total tackles (100), said he's just glad the Rebels are getting the chance.
"Ever since that Highlands game, I couldn't wait to get another piece of them," Arnold said. "Winning a state championship is the ultimate goal, but meeting them again makes that much better."
Last week's game was special for Arnold, too. After Boyle finished off Hopkinsville, he took a few moments to drink in the atmosphere of his final game at Rebel Stadium.
"I just wanted to take it all in," he said.
Mason said Arnold was one of the seniors who spoke up before the game about making their final home game memorable.
"Jacob was the first one," Mason said. "He said, 'Three weeks ago was our senior night, but tonight is the real senior night.'"
That's what a leader does, and Arnold said he learned things like that from those who came before him.
"Last year I looked up to all those senior linemen. This year I kind of stepped into that role," he said. "Leadership is what makes a good team."