When he walks through the school's hallways in his lacrosse uniform, people frequently call him "Coach," although Brunner is not your ordinary freshman — and he's not a coach, either.
He is, however, big — 6- feet 7 and 322 pounds — and a force to be reckoned with on the field.
Moreover, at 40, Brunner is twice the age of many of his Cardinal teammates.
Middle-aged and multi-talented with a lacrosse stick, the father of three sons, Brody, 6, Bailey, 10, and Tiernan, 12, leads the team in goals with 30.
"The kids love him and he loves the kids," CCBC, Catonsville coach Bill Zopp said.
When Zopp found out Brunner was taking classes that would help him get a Master's degree, the coach invited him to play for the Cardinals.
Brunner's sizable impact already has opposing teams game-planning to stop him.
When the Cardinals went on the road to face County College of Morris, N.J., earlier this season, rival players who dubbed Brunner "Sasquatch," implemented an unconventional defensive alignment geared toward keeping his production to a minimum.
"The guy locked me off the whole game," Brunner said.
It worked, sort of, though his teammates picked up the slack in Catonsville's 8-4 victory, the first win of the season after three straight losses.
On April 11, in a 16-15 home victory over Delaware Tech, the Lutherville resident took over the game.
He scored seven goals, including the game-winner with 30 seconds left on a behind-the-back shot off a feed from Catonsville High graduate Greg Abendschoen.
In the first half, Brunner had a stretch of four goals in just 2:04, including two in six seconds that helped the Cardinal erase a 5-2 deficit.
Abendschoen also assisted on one of those, but the game-winner was special.
"It was really the only angle he had," Abendschoen said. "I was excited for him."
Abendschoen first saw Brunner at a pre-season meeting.
"I figured he was going to help coach the team," Abendschoen said. "I was shocked when I heard he was playing."
Brunner does coach his sons on the Lutherville-Timonium Recreation and Chesapeake Rock club teams, which gives him insight into the game that benefit his younger collegiate teammates.
"He's almost like having a coach on the field," Abendschoen said.