Steve Mosko (left)

Steve Mosko, left, a 1974 John Carroll School graduate, poses with Bryan Cranston and Aaron Paul from the hit series "Breaking Bad." (John Shearer | Invision for AMC/AP, Invision for AMC / July 24, 2013)

Steve Mosko was not exactly the best student when he graduated The John Carroll School in 1974.

In fact, "a guidance counselor told me I probably wasn't college material," Mosko, who's since become the head of a major television studio, recalled.

Nor did he initially seem destined for anything too ambitious, spending his high-school summers working as a janitor at the school and the Bel Air United Methodist Church, as well as putting in time at Friendly's at Harford Mall.

"I had every lousy job known to man, but we all paid our way through high school and we paid our way through college," the Bel Air native said.

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Fast forward a couple of years, and Mosko was indeed in college at the University of Delaware, where he first got a taste of working for radio stations in Philadelphia and, ultimately, television.

Fast forward a few more decades, to 2013.

"Breaking Bad," on AMC, is one of the most successful TV shows in recent memory. Sony Pictures Television grows worldwide, expanding channels into 840 million households.

The man behind it all? A certain former John Carroll janitor, now at the helm of one of the biggest television studios in Hollywood.

Mosko, 57, was last interviewed by The Aegis in 2004, about 12 years after he joined Sony Pictures Television as vice president of the western region for Columbia TriStar Television Distribution.

It was also two years later that his job title became a little shorter: President. Of all of Sony Pictures Television.

What has changed since then?

"All of our U.S. business has just gone through the roof," Mosko said last week, by phone from California.

Besides the 124 channels in more than 159 countries, Sony Pictures Television oversees GSN, cable's game show network, has produced prime-time series like "Community" for NBC, "Damages" for DIRECTV, "Necessary Roughness" for USA, "Hatfields & McCoys" for History Channel and "Justified" for FX.

The company also produces syndicated shows like "Wheel of Fortune," "Jeopardy!" "The Young and the Restless" and "Days of Our Lives."

Perhaps the studio's biggest show, however, is entering its last season: "Breaking Bad," about a chemistry teacher who turns to selling methamphetamine after he is diagnosed with terminal cancer.

Mosko said he is glad his company picked up the show despite its odd premise.

"When we first did the show, it was kind of an interesting show because a lot of people wouldn't go near it," he recalled.

"It's been hugely successful in the U.S., here on AMC, and it's as big a hit around the world," he said. "It has some of the most loyal fans I have ever seen in a TV show."

The final season starts this Sunday, and Mosko said he is thrilled with where it stands.

"It absolutely is going out on top and creatively, it's at its peak, and it's very rare that that happens," he said. "It all worked out just right."