BOSTON – He was known to Boston baseball fans as just Jimmy, the kid who 50 years ago inspired one of the largest cancer funds in the world.

After one summer as the symbol of children with cancer, Jimmy had disappeared, but his memory lived, on posters, on billboards, on the minds of all people who knew the cruelty of cancer in children.

Most figured he had died like so many other kids with cancer back in the 1940s. But the boy who launched a thousand fund-raisers when he sang “Take Me Out To The Ball Game” on national radio from his hospital bed simply got on with his life, quietly.

On Thursday, Einar “Jimmy” Gustafson, grandfather and truck driver, returned to Boston where chemotherapy pioneers saved his life, for an anniversary party at The Jimmy Fund Clinic.

On Friday, he will attend a ceremony honoring the fund before the Red Sox-New York Yankees game at Fenway Park, where a sign in right field for years urged people to remember the charity.

Gustafson, whose pseudonym became a legend, is now 62, no longer a bright-eyed boy from New Sweden, Maine.

In 1948, when he was confined to a bed at Boston Children’s Hospital, Gustafson remembers the boys and girls who just disappeared from the cancer clinic, victims of the disease.

“There’s one I’ll always remember,” Gustafson said. “He was the one they pulled the curtain on.”

That was David, a boy with blue eyes and blond ringlets and beautiful parents “right out of the movies.” Einar and David often talked as they lay beside each other.

Then, in those days when so many fights against cancer were lost, David, too, was gone.

“The doctors one day pulled the curtain around him, and, jeez, you wouldn’t know what happened,” he said. “I remember his mother and father crying.”

“Of course millions of parents have been left crying,” he said with his voice trailing off.

Gustafson’s illness first appeared when, as a 12-year-old boy, he found himself doubling over in pain as he walked to school. The rural doctors did what they could. In Caribou, Maine, they operated on his appendix. In Lewiston, they removed part of his intestine.

He did not improve. And one doctor told Gustafson’s parents their only boy was going to die in six weeks.

His family then turned to Boston, where the legendary Dr. Sidney Farber was trying to use chemicals to kill cancer.

Here, in the spring of 1948, Gustafson was diagnosed with what is now called non-Hodgkin’s lymphoma that formed a large tumor on his intestines.

He wasn’t really sure what was wrong with him, but he knew in that barracks-like ward, patients were getting special treatment.

“They were playing around with chemicals and I was the guy they were playing on,” he said.

He remembers many painful shots and bad-tasting vials of medicine administered by Farber, whose experiments would revolutionize cancer treatment.

But he also remembers his nurse, Elizabeth Blumenthal, who cared for him so tenderly she “could make a glass of water taste like a vanilla milkshake.”

And he remembers the day the entire Boston Braves baseball team showed up at the bedside of one of their biggest fans.

As one of Farber’s pet patients, Gustafson was chosen to talk baseball with Ralph Edwards and sing “Take Me Out to the Ball Game” with the Braves on Edwards’ national radio program to raise money for research.

Edwards dubbed him Jimmy. And the radio story and especially the song of tribute to the national pastime – with Gustafson’s voice by far the loudest – started the outpouring of donations for cancer research and was the beginning of The Jimmy Fund in New England.

“It was just a little bubble that mushroomed,” Gustafson said.

Sitting in the blue and white kitchen of his Cape Cod home sipping coffee and petting his cat, Tex, Gustafson recalls an amazing summer 50 years ago with friends like Warren Spahn and Eddie Stanky as if it were yesterday.

He recalls spending that entire summer going to games accompanied by doctors and eating lunch with the Braves at each of them.

And he recalls going home to the northern reaches of Maine, knowing he would probably get better. That was plenty. He never thought of himself as a celebrity, just a lucky kid they never pulled the curtains on.

He finished eighth grade in the one-room schoolhouse in New Sweden and went to high school in Caribou. He married his high school sweetheart, Karen, worked as a trucker and on his family farm. The couple had three daughters and eventually moved to Bourne where he became a carpenter. Karen died of cancer in 1986.

Now Gustafson and his second wife, Gloria, travel the country together while he hauls loads in his tractor-trailer, equipped with two beds, a 19-inch TV and a refrigerator.

Meanwhile, The Jimmy Fund has raised more than $150 million for cancer research.

Everyone in his tiny town of 800 people knew Einar was “Jimmy” but they’re not bragging people. He finally came forward after his sister, Phyllis Clausen, wrote a letter to the fund with her annual donation, telling them that Jimmy was still around.

As he walked through the halls of the clinic that carries his pseudonym, Gustafson was clearly proud of the contribution his image made. He says he’s amazed at how far cancer treatment for children has come.