Connor McMahon knows how dull sitting through chemotherapy can be. To help other children with blood disorders—like the acute lymphoblastic leukemia (ALL) that required him to undergo years of chemotherapy, bone marrow aspirations and spinal taps—stave off boredom during medical procedures, he started Connor’s Hope, an organization that to date has distributed 900 backpacks filled with activities to kids like him, reports People.

When he was first declared cancer-free at age 7, McMahon told his parents he wanted to give the same hope he felt to the kids getting treatment at the Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, where he’d received three years of chemotherapy.

The family got 30 backpacks embroidered with the word, stuffed them with things like coloring books and puzzles, and donated them to the hospital. This was the beginning of Connor’s Hope—and of McMahon’s own saga, which his parents have chronicled on Facebook and CaringBridge.

McMahon’s ALL recurred when he was 12, requiring two more years of chemotherapy, and recurred again in 2016, when he was 15. He enrolled in a clinical trial for CAR-T therapy at Duke University Children’s Hospital in Durham, North Carolina, where he received Kymriah (tisagenlecleucel) in October 2016. A month later, he was declared cancer-free for the third time, and he’s had clean scans since.

McMahon has played hockey since he learned to skate, and on November 7, the now–17-year-old got to meet his favorite player, goalie Henrik Lundqvist of the New York Rangers, on Good Morning America.

Lundqvist’s surprise visit was part of the 20th annual Hockey Fights Cancer initiative, a campaign sponsored by the National Hockey League and the National Hockey League Players Association, to raise awareness of and funding for cancer in the hockey community. McMahon talked about his experience with cancer and how the sport helped him maintain a sense of normalcy during his years of treatment: “While I was on the ice, I wasn’t the kid with cancer; I was a hockey player,” he said.

After years of treatment and testing and a decade of giving through Connor’s Hope, “I think [cancer] made me the person I am now. I think I’m a better person overall because of it,” McMahon told People.

Read more about ALL here, and about childhood cancers here.