For millions of television viewers in the 1970s, few characters were cooler than Arthur "Fonzie" Fonzarelli.

Played by Henry Winkler on the hit sitcom "Happy Days," the leather-jacket-wearing mechanic could start a jukebox with a tap, attract women without trying and seemingly handle any problem with a confident "Ayyyy." But in one memorable episode, Fonzie faced something even he couldn't charm or muscle his way around: his own mortality.

The result was one of the more unexpected faith-centered episodes of a mainstream sitcom during the era.

"Fonzie's Baptism," the Season 4 finale of "Happy Days," aired March 29, 1977. Rather than centering on Fonzie's usual adventures, the episode sent the famously confident character to church as he wrestled with questions about death, God and what would happen to him when his life was over.

And yes, the Fonz ultimately decided to get baptized.

A Near-Death Experience Gets Fonzie Thinking About Eternity

The episode begins after Fonzie survives a frightening stock-car racing accident. Although he walks away, the close call leaves him shaken.

Suddenly, a character who normally seems almost indestructible is forced to recognize that he isn't.

Fonzie begins wondering what will happen when his "number" eventually comes up. Al Delvecchio, played by Al Molinaro, suggests that Fonzie speak with his twin brother, Father Anthony, a Catholic priest.

That conversation eventually leads Fonzie toward baptism.

It was an unusually serious subject for a show built around teenage dating, motorcycles, drive-ins and the everyday adventures of the Cunningham family. Yet "Happy Days" didn't completely abandon its humor to tell the story. Instead, the episode allowed Fonzie to approach faith in a way that still felt consistent with the character viewers knew.

During the baptism ceremony, Fonzie speaks about the Ten Commandments and the importance of loving your neighbor. The congregation and those closest to him also sing "Faith of Our Fathers," the traditional Christian hymn associated especially with Catholic communities.

The episode stands out nearly 50 years later because it didn't merely mention religion in passing. Faith was central to the storyline, with Fonzie actively seeking spiritual guidance after confronting the possibility of death.

Fonzie Had Talked to God Before

"Fonzie's Baptism" wasn't the first time Winkler brought a spiritual dimension to the character.

Years later, Winkler recalled an earlier "Happy Days" scene in which Fonzie was asked to say grace at the dinner table. Rather than deliver a long, traditional prayer, Winkler believed Fonzie would speak to God in his own unmistakable way.

"Hey, God? Whoa," Winkler recalled saying.

That short line carried far more meaning in Winkler's mind. He explained that the "whoa" expressed gratitude and thanks, and he reportedly had to make his case to keep the prayer short rather than have Fonzie deliver a longer speech.

The moment worked because it fit the character. Fonzie wasn't suddenly transformed into someone else when he talked to God. His prayer sounded like Fonzie.

That same instinct helped make the baptism storyline believable. The character could wrestle with serious questions without losing the personality that had made him a television phenomenon.

Henry Winkler Helped Make Fonzie an Icon

Winkler's influence over Fonzie extended far beyond his approach to faith.

One of the character's most famous mannerisms came from a scene involving a mirror and a comb. Fonzie was supposed to comb his famously perfect hair, but Winkler had made a personal decision that the character was too cool to admire himself that way.

"I can't comb my hair, I made a deal with myself," Winkler recalled telling the director in a 2015 interview with The Guardian.

Since the action was already in the script, Winkler found another solution. Fonzie approached the mirror, raised the comb and realized his hair was already perfect.

"Heeeey," he responded.

Winkler said Fonzie's famous "Heeeey" and "Whoaaa" were inspired in part by horseback riding, one of his favorite sports at the time.

The small choices helped transform Fonzie from a supporting character into one of television's most recognizable personalities.

Fonzie Wasn't Even Part of the Original Plan

Even more remarkable is that "Happy Days" creator Garry Marshall didn't originally include Fonzie in the show.

Marshall later explained that he decided the series needed a different kind of personality to shake things up. Inspiration came from a tough neighborhood character Marshall remembered from growing up in the Bronx.

"I grew up in the Bronx and patterned him off a guy in my neighborhood called Anthony," Marshall once explained, recalling that the man could perform an astonishing feat involving pulling an ice truck with his teeth.

Fonzie eventually became far more than a character who simply shook things up. He became a defining symbol of "Happy Days" and one of the biggest pop-culture figures of the decade.

Winkler's performance earned him multiple Emmy nominations and helped turn leather jackets, thumbs-up gestures and a simple "Ayyyy" into pieces of television history.

A Different Kind of 'Happy Days' Memory

"Happy Days" ultimately ran for 11 seasons, from 1974 to 1984, following the Cunninghams and their friends through a nostalgic version of 1950s and early 1960s America.

Among all those episodes, "Fonzie's Baptism" remains unusual.

There was no attempt to turn the entire series into a religious program. Instead, the episode took one of television's coolest and seemingly most fearless characters and allowed him to admit that he had questions he couldn't answer himself.

For a brief moment, Fonzie wasn't worried about motorcycles, girls or maintaining his reputation. He was thinking about God, death and eternity.

And for one episode of one of the biggest sitcoms on television, even the Fonz decided being cool wasn't enough.