(WIVB) — The Bills’ athletic trainer who saved the life of Buffalo Bills safety Damar Hamlin made a rare public speaking appearance on Saturday, delivering the commencement address at his alma mater, Oklahoma State University.

In his speech to the graduates, he discussed the night that he said changed the course of his athletic training career, when Hamlin suffered cardiac arrest in the Bills’ game against the Cincinnati Bengals on January 2.

His quick thinking and life saving measures saved Hamlin’s life.

“For his family, his teammates, his coaches, our athletic training staff and the millions of football fans watching in the stadium or in the comfort of their living room TVs, it was a scary moment to say the least,” Kellington said. “Thankfully, we restored Damar’s heartbeat. We were ready.”

Kellington has been hailed as a hero since the collapse, but said that he was just doing his job.

“It’s a bit odd to be the person reporters are talking about, when they say Denny Kellington is a hero, it’s very humbling. In fact, all the attention I’ve received for simply doing my job has been overwhelming,” he said. “I’ve said repeatedly that I am not a hero, but I’ll tell you what I was that day: I was ready.”

Since January, Hamlin has used his platform to advocate for learning about CPR and AED, which Kellington said will save lives.

“I have no doubt that this moment, caught on the world stage, is going to save many more lives,” he said.

Kellington said that he has turned down several public speaking requests since January, but decided to this one for his alma mater. He is a 2000 graduate of the school with a degree in health and human performance.