Wayne Treacy was sentenced Monday for the attack that left 15-year-old Josie Lou Ratley with permanent brain injuries.
Broward Circuit Judge David Haimes sentenced Treacy to 20 years in prison with 10 years probation. He was facing a maximum of 50 years and a minimum of 15 years.
Treacy showed no emotion but his stepfather did.
"What if my kid would have went down to the tree and hung himself in the same spot? Where would Josie be now? Out there free, running around," said Cary Smith, Treacy's stepfather.
The sentencing hearing Monday was emotional at times, especially when two letters to the judge were read.
"God knows nobody can possibly condone or excuse what happened, and Wayne is profoundly aware of that," said Sandra Manon, a friend of Treacy's family. "He has endured punishment beyond what most kids with his mental condition would be able to bear."
The other letter was written by Josie Lou Ratley's mother.
"Do you feel sorry for what you've done? Do you pray to God and ask forgiveness, or ask your parents, 'Why did this happen?'" said Sean Domnick, a friend of Ratley's family. "Wayne, I don't think your capable of feeling or knowing who God is. But you know, Wayne Treacy, Josie and I know God, and we pray to God you never hurt anyone else again."
In July, a jury found Treacy, now 18, guilty of Attempted First-Degree Murder with a Weapon. Treacy was convicted of throwing Josie Lou Ratley to the pavement, slamming her head against the concrete, and kicking her with steel-toed boots outside Deerfield Beach Middle School in March 2010. He did it in response to a taunting message Lou Ratley had sent him about his older brother, Michael, who had committed suicide.
During the sentencing hearing Monday, mental health experts took the stand for both sides, each agreeing Treacy suffers from mental illness, but prosecutors said he knew right from wrong. Both sides told the judge Treacy was in need of extensive treatment, though prosecutors insisted it should be followed by prison time.
"Wayne is a high suicide risk and if he doesn't get the treatment he needs, he will kill himself," said Dr. Alexander Neumeister, a defense witness.
Treacy is currently in a solitary cell in the Broward County jail under suicide watch.
Earlier in the day, Kayla Manson pled no contest to reduced charges for her role in the attack.