Peter Samson, 67, who built Radnor’s youth lacrosse programs into sprawling affairs involving thousands of area boys and girls, and who created the Katie Samson Lacrosse Festival and Foundation, attracting teams from all over the state, died Saturday, Aug. 17, following a bicycle accident in Little Compton, R.I., near his summer home in Westport, Mass.

Mr. Samson was taken immediately to St. Anne’s Hospital in Fall River, Mass., where he died a few hours after the accident, his family said. There were no other vehicles involved.

“Peter started the Radnor Youth League almost 30 years ago,” said John Begier, head lacrosse coach at Radnor High School. “He’s a legend in the town of Radnor.”

Mr. Samson, a trial lawyer, was passionate about lacrosse, which he played at the University of Pennsylvania in the early 1970s, and he had an ability to communicate that passion and the skills of the game to kids, according to a number of friends and colleagues.

He founded the Radnor Youth League about 1990.

“He’s been a driving force behind youth lacrosse in Radnor,” said Begier.

“It was a passion,” recalled Mr. Samson’s son Brian, who played the game at Radnor High School and at Georgetown University, and now coaches as well. “It wasn’t always an easy thing. In the early days, he’d be lining fields and going all over the township.”

But the program caught on.

“If you were a family coming into the area and getting your son started — the fun and joy started with him,” said Begier. “Peter was so passionate — for every kid, for every underdog. He wanted everyone to have a chance.”

In 2017, Mr. Samson retired from coaching the youth league — for a year. He returned this year, and also took on coaching duties at Radnor High School.

Mike Friel, a longtime friend and Radnor’s athletic director, said having Mr. Samson on the coaching staff was a remarkable experience.

“Our kids loved him,” Friel said. “The biggest thing is that thousands of families have played and been involved with lacrosse over the years — that’s all because of Peter.”

Mr. Samson also organized the Katie Samson Festival and Foundation, named for his lacrosse-playing daughter whose career — which included the 1999 Division III national championship as goalkeeper for Middlebury College — ended following a sledding accident in January 2000 that left her paralyzed.

Her injury led to the formation of the foundation and festival named for her, raising nearly $2 million for spinal cord research.

Mr. Samson also had a successful career as a lawyer, most recently with the firm of Cipriani & Werner, where he focused on medical malpractice and litigation involving universities.

“We are all deeply affected and saddened and still in shock about the tragic loss of our friend Pete,'” said the firm’s co-managing partner, John F. Hayes II. “He had a kind and humble and humorous spirit. His prowess on the lacrosse field was exceeded only by his ability in the courtroom. His vast successes as a trial lawyer made him a great mentor and a helpful strategist to his peers.”

“My dad was a highly successful attorney and built a remarkable career,” said Brian Samson. “His hobby and avocation, besides being a great dad, his great joy was in coaching children. He was a child at heart and poked innocent fun at you. That playfulness balanced the sports and competition.”

In 2017, Mr. Samson was inducted into the Eastern Pennsylvania Chapter of the U.S. Lacrosse Hall of Fame. At the 2009 U.S. Lacrosse Convention, he received the coveted Founders Circle Award for his work in Radnor.

In addition to his son Brian, Mr. Samson is survived by his wife, Lynne; children David, Katie and Molly; four grandchildren; and his first wife, Banny Ackerman.

Funeral arrangements are pending.