The series follows nine students in their final year of high school in 2000, and also explores their lives ten years later.
King told TV Guide that she had enjoyed shooting in a mockumentary style.
"It's amazing," she said. "As an actor, you have to totally think about the scene differently. Imagine you're a real person and you have a documentary crew following... you. The way that you would act in a situation would be different."
She added that she had found it "fascinating" to play her character Jacqueline Vachs at two different stages of her life.
"I was a totally different person ten years ago," she explained. "[The] consciousness [of the characters] is so different, the way they think about things and look at things and talk. Everything that comes out of their mouths is to impress the people around them."
The 31-year-old actress also joked that she had felt odd playing a high school student.
"It's really fun playing an 18-year-old," she said. "I laugh because I'm the only 31-year-old wearing a frickin' cheerleading costume."
My Generation premieres on September 23 at 8/7c on ABC.