He spoke only to confirm his name and his guilty plea to killing Hardenuish School pupil Ellie on May 3 this year.
He will be sentenced on Friday, November 8.
Richard Smith appeared for the prosecution and Peter Binder for the defendant.
In a statement released shortly after her death, Hardenhuish School said it was "shocked and saddened" by Ellie's death.
"Ellie was a talented, popular and much-loved member of our school community who will be dearly missed," it said.
Headteacher Lisa Percy added: “Ellie was a well-loved, popular and bubbly student." The school organised a balloon release in the girl's memory.
A week on from the talented horse rider’s death, Wiltshire Police's chief constable Kier Pritchard paid tribute to the girl: "My officers have seen first-hand the outpouring of love and support being shown by the people of Calne and Chippenham.
"I would like to pay tribute to everyone who knew Ellie. From the recollections I've been told by the head teacher at Hardenhuish, Ellie was a vibrant, popular and talented young woman.
"I, like many of you, have children of a similar age to Ellie and I simply cannot comprehend the grief and sadness all those affected are feeling. I fully appreciate the disruption, uncertainty and concern this case would have caused in what is a quiet but close-knit community."