Nick Roses.

Has there ever been a more perfect name for a Hollywood talent manager? It’s so perfect that one might wonder whether the guy had turned his lemon of a real name into lemonade, as per Hollywood tradition—the way Irving Lazar became Swifty Lazar and Sam Goldfish became Samuel Goldwyn. But damned if his birth certificate doesn’t read “Nicholas Tomas Roses.” The name of his hometown in Florida? Hollywood. Some guys are just naturals.

Last year, Roses started his own company, Total Talent Management, where he handles the careers of 50-odd actors. It’s a manager’s job to arrange auditions, shape a client’s career path, and generally do whatever he can to get the clients jobs. If you fail to see a distinction between a manager and an agent, that’s because there barely is one.

Roses’s business is a bit more specialized, in that most of his clients are between the ages of 6 and 17. He is among the subset of managers who focus on what Hollywood calls “young performers” and everyone else calls “kids.” The child-rep business, once largely ignored by the biggest agencies and management companies, is booming like never before. The onslaught of kid-friendly cable TV networks (Nickelodeon, Disney Channel), coupled with the rise of TV talent competitions, puts every child just one audition away from becoming the next Miley Cyrus or Zac Efron. This makes for a motivated client base.

Roses has been in the management game since 2002. Which isn’t all that noteworthy until you discover he was born in 1989. Which means Roses was younger than some of his clients. And he looks the part. At work, he favors cuffed gray jeans and a formfitting T-shirt, and he tends to tug and flip his shaggy blond hair. To visit him in his office in Burbank is to find a flaxen-haired cherub surrounded by big gym balls (for exercise) and little squeak-toys (for the office dog). But he talks the talk, albeit in the voice of his generation. He says, “What I...