"When you go through something like, you learn to appreciate little things – the birds, trees, flowers," the actor, 36, tells PEOPLE at a restaurant across from the actual 30 Rockefeller Center. "I pay attention to everything now – the taste of bread, the taste of water. It all feels different now."
After suffering with hypertension for 13 years, the 7-ft.-tall celebrity-bodyguard-turned-actor experienced kidney failure in 2008. Undergoing dialysis three times a week, Chapman – who once weighed 505 lbs. – reduced his food intake, cut out cheese and mayonnaise and started walking to shed the necessary 160 lbs. to be eligible for a kidney transplant.
"I didn't want to die," he says. "I wanted to live. I wanted to be with my family and wanted to see my 11-year-old son grow up." Chapman also has a daughter, 19, who is in the Navy.
Donor Not Even a 30 Rock FanMuch to Chapman's surprise, a 20-year-old single man in Arizona stepped forward to give him a kidney in May. Unaware of Chapman's search for a donor, the altruistic young man had simply contacted the National Kidney Foundation and soon began testing to see if he were a match.
"He wasn't a fan of 30 Rock and didn't watch it.," says Chapman. "He was a total stranger who was going to donate a kidney, regardless."
The donor, who does not wish to be identified, flew out to New York's Montefiore Medical Center for the transplant and spent several days recovering from the surgery. He and Chapman have remained in close contact ever since, chatting by phone, emailing or texting each other nearly every day.
"We talk all the time, all the time," says Chapman. "He just sent me some pictures from a wonderful trip he took, and I told him I was a little jealous. Next time he goes, I am going with him."
After spending the summer recuperating, Chapman resumed filming 30 Rock a few weeks ago. As for any surprises viewers might expect in the season ahead, "The only thing I can give you is that Matt Damon will be back really soon," he says.
On Oct. 17, 2010, Grizz Chapman will be leading a team of walkers in the National Kidney Foundation annual walk in downtown Manhattan. For more information, go to Team Grizz. For further info about kidney disease and organ donation, go to the National Kidney Foundation Web site.