Walter Herbert, nicknamed "Superbubz" by his friends and family, was fighting stage 4 neuroblastoma, a form of childhood cancer.
Chive Charities, an organization dedicated to helping individuals with rare medical conditions, helped the Herbert family meet Votto at the Reds clubhouse the week before the home run.
Votto called Superbubz "one of the most special young people I've ever met in my life."
Herbert’s father, Wally Herbert, thought Votto might say "hello" to his son as he walked by the stands that day. When Votto came over for a high five and then gifted him the bat and jersey, "I kind of lost it, personally," the elder Herbert said.
Moments like those, he said, helped buoy Superbubz through cancer treatments and other less rosy experiences.
"What (Votto) did for Bubz was amazing," he said. "I was tearing up. You can't have a better day than we had today."
The Reds invited Herbert back again, this time to be an honorary team captain.