It was the first public interview yesterday given by any of the three women who were held captive by rapist Ariel Castro since their dramatic escape on May 6.
Knight was the first to be snatched off the street in 2002 when she was 20 years old.
In a paid interview with the Dr Phil show, the diminutive woman described how Castro had been hoping for a younger victim.
A year later Castro captured 16-year-old Amanda Berry. He kidnapped 14-year-old Gina DeJesus in 2004.
The women escaped when Berry managed to break open part of the front door and call out to a neighbor for help. She emerged from the dilapidated house with her young daughter who was fathered by Castro during her captivity.
Police found Knight and DeJesus huddled in fear upstairs.
More than 92 pounds (42 kilos) of chains were found in the filthy, darkened home where the women were kept in locked rooms with boarded-up windows.
Knight, who was also the only victim to speak at Castro's trial, reportedly suffered the worst abuse. Court documents described how Castro forcibly terminated five of her pregnancies by beating and starving her.
In the first of two taped episodes, she told psychologist host Phil McGraw that Castro blamed her for the first miscarriage after he slammed a barbell into her stomach.
She described painful and degrading rapes, vicious beatings and constant threats.
"'You're not supposed to be crying you're supposed to be happy.' That was his little fairy tale world."
Knight said she could often hear visitors in the home, but Castro prevented her from calling for help by stuffing a "dirty, nasty sock" in her mouth and covering it with duct tape.
