This once out-of-shape workaholic survived cancer and a heart transplant. He now inspires others to live life full-tilt.

In May, Ironman triathlete Derek Fitzgerald will attempt to cycle for 24 hours straight as part of a fund-raising campaign for the Leukemia & Lymphoma Society.

His goal: to raise $57,000 — equal in dollars to the number of people lost to blood cancers every year in the U.S. He’s also hoping to inspire others to get on their bikes, not necessarily to ride 24 hours nonstop but to fund the fight against the disease.

His own battle against cancer was utterly brutal — and spectacularly triumphant.

Last December, he celebrated 17 years in remission from non-Hodgkin lymphoma. The next month, he marked 10 years living with a donor heart. His own had been irreparably damaged by the chemotherapy that saved his life from cancer.

Since then, said Bill Bulat, campaign development manager of the Leukemia & Lymphoma Society of Eastern Pennsylvania and Delaware, Fitzgerald has been an indefatigable soldier in the war on blood cancers.

“Derek is an incredible representative of our campaign, not only because of his personal story but because of the work he continues to do,” Bulat said. “He’s a standout leader in our community who helps people across the country find hope.”

Fitzgerald, 48, had never aspired to be an athlete. Although he played soccer and baseball while growing up in Warminster and Lansdale, he pivoted in college to focus on career goals — first in television, then in computer programming. He married, started his own company, and spent his twenties building success while neglecting his well-being.

“I was working 20-hour days. I would grab food from a drive-through,” he said. “I was sitting on my rear-end all day. My gut was making my buttons pop on my button-down shirts.”

His workaholism ground to a halt in 2003 when a scan revealed that a grapefruit-sized tumor was growing on his intestines. A biopsy revealed he had non-Hodgkin lymphoma. He was just 30 years old.

The surgery to remove the growth was grueling. Afterward, he needed three months of physical therapy before he could even began five months of chemotherapy, whose side effects left him weak and exhausted. Finally, his cancer was declared in remission.

Three months later, though, Fitzgerald started having difficulty breathing. Fluid would collect in his lungs, dizzy spells would hit, and the world would spin.

Finally, he underwent a cardiac stress test, which yielded stunning news: He was in cardiac failure. One of the medicines meant to keep his cancer from returning had severely damaged his heart.

Over the next seven years, his heart weakened and his now-overtaxed other organs began to fail. In August 2010, he was placed on the waiting list for a heart transplant. That Thanksgiving, he tried to make peace with the fact that it would probably be his last one.

By New Year’s Day 2011, Fitzgerald was dying at the Hospital of the University of Pennsylvania. Then, on Jan. 3, the transplant coordinator entered his hospital room.

“She was crying,” Fitzgerald recalled. “She said, ‘We think we’ve found your heart. Do you still want to go through with this?’ ‘I said, I don’t have a choice, do I?’ She said, ‘No, you don’t.’ I said, ‘OK, let’s do this.’”

The next morning, post-transplant, he woke surrounded by a bank of beeping machines — and felt the astonishingly strong thump of a healthy heart inside his own chest.

The reality of the gift overwhelmed him.

“I was just grateful to be alive,” he said. “I wanted to do everything I could to find a way to give back, to earn what I’d been given.”

During cardiac rehab, as he worked his way up to a very slow jog, he felt a real connection to his organ donor.

“I’d basically have these internal dialogues with this person’s heart,” he said. “I’d say, ‘That felt amazing. Do you want to try a little more?’ If you keep asking for the slightest improvement from the day before, over time you’re going to improve in ways you never dreamed possible.”

Eight months later, Fitzgerald ran his first 5K. Two months after that, he ran his first half-marathon. In January 2012, a year after his transplant, he started training for a triathlon — part of which included running the Philadelphia Marathon. He built a gym in his basement and worked out. He focused on his nutrition.

“In July of 2013,” said Fitzgerald, “I became the first cancer-surviving heart transplant [recipient] to do a full 140.6-mile Ironman triathlon in Lake Placid, N.Y.”

As proud as he was of his extraordinary accomplishment, he felt a responsibility to help others live fuller, healthier lives by sharing with them the lessons he had learned the hard way. So when he began getting asked to speak to community and business groups about his experience, he jumped in with gusto. He’s now a favorite on the public-speaking circuit.

“My goal is to help people see what physical activity can do for their lives,” said Fitzgerald, who lives in Doylestown with his wife, Erin. He shares custody of his daughter Emma, 7, with his first wife, and he works as a motivational speaker and marketing consultant. “It’s not about doing an Ironman. It’s about getting outside and enjoying life — life isn’t all about work and making money. There needs to be some kind of balance there.”

He hopes his story will help people realize, as he did, that they are capable of doing and being more than they ever could imagine.

Meantime, he has launched The 156 over 24 Challenge to raise money to fight the blood cancers that kill 156 Americans every 24 hours. It’s a 10-week campaign for the Leukemia and Lymphoma Society’s Man & Woman of the Year, “a philanthropic competition to support blood cancer research among a group of motivated and dedicated individuals in communities across the United States.” Fitzgerald’s campaign will support research into precision medicine. On May 22, Fitzgerald will hop aboard a Peleton bike for his 24-hour pedal session. Between now and then, he hopes his story will inspire others to join with him to do what they can for the cause.

It’s all in thanks for the life he almost lost — twice.

Said Fitzgerald, “I’m going to spend the rest of my life trying to earn this gift.”

For more information about Fitzgerald’s campaign, visit recycledmanspeaks.com.