Who Played Eugene on Happy Days? Henry Winkler Gave Him a New Name!

Henry Winkler, who played Arthur "Fonzie" Fonzarelli on the classic sitcom Happy Days, has publicly called out a former co-star for letting fame go to his head. The 80-year-old actor made the remarks during a panel at Fanboy Expo Knoxville in July alongside former castmates Anson Williams and Don Most.

While Winkler praised the overall atmosphere on the set, he singled out one guest star who repeatedly bragged about his fan mail. Winkler didn't say the actor's name directly but identified him by his character.

"He played Eugene," Winkler said, according to Entertainment Weekly.

The character in question is Eugene Belvin, a nerdy recurring role who appeared in 10 episodes across seasons 8 and 9 of the show from 1980 to 1982. Eugene was part of Joanie Cunningham and Chachi Arcola's friend circle and had a well-documented crush on Jenny Piccolo.

The actor behind Eugene Belvin is Denis Mandel.

Credit: Tommaso Boddi/Getty

'There Was No Stardom'

Winkler described the Happy Days set as largely free of ego.

"The truth of the matter is really on our set, there was no stardom," Winkler said. "We were an ensemble. We worked hard at making it funny every week."

But then he recalled one exception.

"There was no— one guy came on as a guest star, and then he was brought back a few times," Winkler said. "And he would mention his fan mail. And I said, 'You don't wanna talk to me about fan mail. I got 50,000 letters a week.'"

Winkler said he told the actor the set wasn't the place for that conversation.

"And I said, 'We don't talk about that on the set. We are all here as one,'" he recalled. "And he kept doing it, and he was an assback."

Who Is Denis Mandel?

Denis Mandel played Eugene Belvin in a recurring capacity during the show's eighth and ninth seasons. Beyond Happy Days, Mandel appeared in other television series including Knots Landing and Homefront before stepping away from acting entirely.

His last on-screen appearance was in 2006, according to IMDb.

Mandel's character Eugene first appeared in season 8, with the episode "Dreams Can Come True" marking his debut alongside Harris Kal as Bobby.

The role spanned 10 episodes total across the two seasons.

Mandel has kept a low profile in the years since leaving acting. A 2021 profile noted that "he obviously wants to keep his private life private".

Entertainment Weekly has reached out to Mandel for comment on Winkler's remarks.

Winkler Reflects on Howard

Elsewhere during the Q&A session, Winkler spoke warmly about his relationship with co-star Ron Howard, who played Richie Cunningham on the show.

Winkler recalled a moment when he was struggling with a scene and started punching his script. Howard stepped in.

"[Howard] put his arm around me, he walked me to the back of the soundstage, and he said, 'You know, the writers are working as hard as they can. Let's not hit our script,'" Winkler remembered.

Winkler took the advice seriously.

"I said, 'Ron, I will never hit my script as long as I live,'" he said. "And he is, and was, even at that tender age, so wise. He just is easy, he just kind of goes through life and he's an amazing fellow."

Winkler also recalled encouraging Howard about his directorial ambitions while they stood backstage at Arnold's, the diner that served as a central setting on the show.

Howard asked Winkler what he thought about his chances. Winkler's response was emphatic.

"I said, 'Ron, I promise you. If you were a brain surgeon, I would be your first patient whether I needed it or not,'" Winkler said.

Winkler later played the lead role in Howard's sophomore directorial effort, Night Shift, in 1982.