The 20-year-old model spoke out in Los Angeles County Court on Thursday (13.10.16) to testify against Shavaughn McKenzie, who faces one count of misdemeanour stalking.
Kendall appeared shaken and nervous as she told the judge she had found the man sitting in front of the driveway of her home with his head tucked between his knees on August 14.
She explained how she drove around him and saw her gate close, but didn't realise he had followed her into the Hollywood Hills estate until she saw him in her car mirror.
Kendall screamed "Who are you?" but the man just stared at her. She wound her window down six inches and shouted at him to leave, prompting him to begin banging on her windows.
According to TMZ, she admitted: "I've never been so scared in my life."
The 'Keeping Up With the Kardashians' star pulled out of her driveway, drove down the street and called a friend for help.
She will return to the witness stand later in the day.
Earlier on Thursday, a judge imposed a permanent restraining order on McKenzie, with the five-year agreement ordering him to stay 100 yards away from her, her home, her car and her workplace.
It was previously claimed McKenzie had previously camped outside Kendall's home and chased her car as she left, even running into the traffic.
He has previously been arrested for trespassing multiple times at UCLA and surrounding buildings, and his booking at Kendall's home reportedly marked a probation violation.