Bill Jenkins spat at Sion Jenkins, shouted abuse and tried to attack him outside Lewes Crown Court, East Sussex.
The dead girl's natural father had to be held back to prevent him reaching Sion Jenkins, who was rushed into the building by minders.
Sion Jenkins, 41, is charged with murdering 13-year-old Billie-Jo on 15 February last year. She was found bludgeoned to death on the patio of her foster family's home in Hastings.
She had been fostered by Sion Jenkins and his wife Lois for four years.
Sion Jenkins was deputy headteacher of William Parker Boys' School in Hastings until he was suspended as the result of the criminal investigation.
Billie-Jo's natural mother, Debbie Woods, who is estranged from Billie- Jo's father, was also in court yesterday to watch legal argument in advance of the trial, which is expected to start today.