David Perry Jr. came up with the idea to his locks shorn for his cousin Olivia Pena when the two first met about a year ago at a family reunion, The Denver Post reported.
Olivia has Clouston syndrome, which has left her unable to grow hair.
"Right now, [Olivia] has little tiny hairs that look like she's almost going through chemo," said her mother, Melissa Monarez. "Within the last six months, she realized that she's not like her sisters. I comb her sisters' hair, and she asked me to comb her hair."
David told staff members at The First Tee of Green Valley Ranch, a youth program he participates in that incorporates golf and character development, about his plan for his first haircut. The organization's employees helped make it happen, lining up Luxe Salon in Denver to do the haircut.
"It was pretty amazing to hear a 10-year-old come up to me and say he's not cutting his hair unless it is for his cousin," program director LindaSue Chenoweth said.
On Tuesday night, David had three ponytails, ranging from 13 to 20 inches in length, cut off.
The amount is likely not enough for an entire wig, but First Tee President Kevin Laura said the organization will work with a manufacturer to complete it.
"We're ready to make this wig happen whenever Olivia's mom makes the call," Laura said.