If stars are made rather than born, then credit Stagedoor Manor performing arts summer camp, and longtime production director Konnie Kittrell, for helping to mold quite a few. In fact, Robert Downey Jr., Natalie Portman, Lea Michele, Zach Braff and Jon Cryer are all alumni of the program — members of what’s known as the Stagedoor Mafia.

Time flies: Stagedoor started in New York about 36 years ago and has trained thousands of young actors, many of whom have gone on to success in film, television and theater. Kittrell — who works as a college mentor when it’s not summer — has been part of the camp for so long she’s lost track. It’s been “about 32 or 33 years,” she says.

Self-discovery: Kittrell sees Stagedoor as a place where middle-school and high-school students who don’t fit into the culture of sports camps can experience a place where their peers share an interest in the arts. “These kids find people who validate their passion for theater and performance here,” she says.

Role call: With room for 108 girls and 84 boys in each of the three 3-week-long sessions, beds sell out — at $5,645 each — by the end of the summer for the following year. Kittrell, part of a five-member team, puts together approximately 14 shows every three weeks, casting each camper in a role. “I have to think about who’s going where, and is this an opportunity for them to be successful — an opportunity for them to discover something new about themselves,” she says.

Celebrating the arts: Kittrell emphasizes that despite the success of the program’s alumni, ultimately the camp is not about casting, but rather about the campers becoming better artists. “Our goal is to celebrate what it is about theater that makes their heart beat faster, makes them thrive and accept themselves as an artist,” she explains. “Our motto is ‘process not product.’ ”

Relatable journey: Because of the extensive network of Stagedoor alumni, Kittrell says she is often able to connect them with each other. One time, Cryer called a Stagedoor alum to offer congratulations on being cast in a small role in “The Hunger Games.” “You just couldn’t ask for a better job than this,” Kittrell says.