Ron Paolillo goes over the play "The Glass Menagerie" with students at G-Star School of the Arts in West Palm Beach Wednesday. Paolillo, the actor who played Arnold Horshack on the popular ABC sticom, "Welcome Back Kotter," is a teaching acting class at the school. (Gary Coronado/The Palm Beach Post)

“Oooooh-oooooh-ooooh, Mr. Kotter!”

That’s how we remember Ron Palillo in a classroom, playing the cut-up Arnold Horshack on the popular TV series Welcome Back, Kotter.

So what’s this? The Sweathog is Mr. Kotter?

“Open your books, grab a chair and pay attention,” Palillo good-naturedly instructed a class full of ninth graders recently. “Circle things you don’t understand. You never know what might come up as an extra credit on a quiz.”

No longer the geeky class clown, Palillo is in a new role — teaching acting at G-Star School of the Arts in Palm Springs.

It’s hard to picture the white-haired Palillo shaping impressionable young minds considering he remains so closely associated with a character who often acted as if he was losing his.

But Palillo has lectured in colleges and high schools all over the country for years and isn’t worried. “From the moment I heard about G-Star seven, eight years ago, it sounded like everything I wanted as a student when I went to high school,” says Palillo, who is now — gulp! — 60.

“To have this when I was a kid would’ve been astonishing and I knew I wanted to be part of it.” Greg Hauptner, G-Star founder and CEO, says Palillo asked to join the charter school after working with the students on the film Dog Gone Tale: Destiny’s Stand.

“I almost fell out of my chair,” Hauptner recalls. “I didn’t think he was serious.”

The University of Connecticut graduate is teaching entry-level acting his first year. Next year he’s scheduled to run the school’s adult education program.

It’s all been a whirlwind. Palillo got the job in July and barely had a month to prepare for his move from New York to Florida.

“I didn’t think we started until September,” he says. “It’s been absolutely crazy — the moving, coming down, the preparation. I’m a night person who doesn’t go to bed until three, four in the morning, but now I’m going to bed at 10 and getting up at five to be at school at seven. It’s totally turned my life around, but I’ve been doing it happily.”

That’s in part because Palillo loves Palm Beach County, having served as artistic director for the Cuillo Center for the Arts where he directed and acted in A Closer Walk with Patsy Cline and The Phantom of the Opera.

“I’ve always felt very at home here,” Palillo says. “People go out of their way for you in West Palm Beach. They don’t do that in New York.”

Wearing cuffed cream-colored pants and an off-white shirt with pink stripes, Palillo looks South Florida tropical during his second week of class. You’re not sure if he’s going to work or attending an upscale yacht party.

It’s work.

Today’s assignment: Reviewing scene two of Tennessee Williams’ play, The Glass Menagerie. Two students volunteer to read the main characters — Laura, the overbearing mom and Amanda, her slightly crippled daughter.

During the readings, Palillo, like most good teachers, stops the kids several times to explain everything from the Daughters of American Revolution to the meaning of an implicit threat to how a Victrola worked. He also wants the kids to project as if they’re performing at a 500-seat Broadway theater and not inside some cramped high school classroom. It’s obvious Palillo is extremely passionate about his work. There are very few reminders of Arnold Horshack’s nasally whine on this steamy Thursday morning as Palillo’s eyes remain intensely focused on the two students who are reading.

“What did you just say?” Palillo kindly asks as one of the students mumbles her line. “You either have to speak more clearly or I have to get my hearing checked. One or the other.”

Palillo then goes into theater actor mode and impressively demonstrates how Amanda’s line should be read with feeling and conviction. The kids giggle. Palillo doesn’t.

So far, Palillo’s students are giving him a passing grade.

“He lets you talk and express yourself,” says Amanda Hudson, 14. “And I talk a lot so I get to have a lot of fun.”

Palillo stresses the importance of getting his students comfortable with telling unrehearsed stories. “I want them to get the feeling of what it’s like to be totally unprepared and to bond with each other in a way scientists think perhaps primitive man bonded by sitting around the campfire and eating a pterodactyl leg and saying, ‘I caught a brontosaurus this big last night,’” he says, laughing. “It also helps to create a good ensemble.”

The Welcome Back, Kotter cast worked as a well-oiled ensemble from 1975 to 1979. That was no accident. Palillo says the actors paid careful attention to their characters. “The writers asked us to write our characters’ autobiographies as our characters,” Palillo remembers. “I wrote how Arnold’s mother had been married so many times and how he just wanted to be liked and how no one was going to read this autobiography he was writing. The writers used all of it.”

Palillo says he’s still often recognized as Horshack. But unlike many famous actors who attempt to distance themselves from the iconic role that made them a household name, Palillo doesn’t. “It’s a part of my life,” he says. “Why not embrace it as a part of who you are?”

And just how would Palillo teach his TV alter ego?

“I wouldn’t teach Arnold Horshack,” he says. “He was the smartest kid in school, but he opted to become liked rather than being what he was capable of. The Sweathogs were underachievers. These kids at G-Star aren’t underachievers. They want to be here.”