When he’s not running bases for his travel baseball team, 11-year-old Garrett Lowry has an unusual hobby: knitting hats for kids with cancer.

The Denver tween learned to knit 4 years ago, taught by his grandmother as a calming activity for his energetic nature. Last year he set out to knit 15 caps to provide head coverings for kids who lose their hair to chemotherapy. His competitive nature took over and he quickly knocked that goal out of the park. To date, he’s knitted more than 100 caps that he’s donated to hospitals in Colorado and California.

Garrett’s focus on cancer victims comes from losing his grandfather and a beloved cat to the disease. He also has a 5-year-old friend with neuroblastoma, a type of cancer that starts in nerve cells.

“She’s my hero,” Garrett says of friend Riley Rose Sherman. “She does a lot of things other people can’t. This young girl is fighting pain like no one I know can.”

He recently visited Riley and delivered 50 hats to the Children’s Hospital of Orange County, California, where she’s being treated.

Garrett’s generosity goes beyond his loom and yarn. He recently rallied his baseball team to donate gifts to underprivileged families. And when he turns 12 in June, he plans to volunteer at the Colorado hospital where he delivered his first batch of caps.

These experiences sparked a deeper commitment to kindness. “I met quite a few kids that influenced me to do even more,” he says. “I knew I had to do something to help others.”