Michael Holahan, 57, of Elkins Park, a merchant for three decades at the Reading Terminal Market who became one of the venerable institution's most influential forces, died Wednesday, March 16, of heart failure at Abington Hospital-Jefferson Health.

Mr. Holahan and his wife, Julie, opened the Pennsylvania General Store in 1987, when "the market was all beat up," longtime friend Brent Cossrow said.

"In a very understated and not visible to the public way, he helped to change the market," said Cossrow, vice chairman of the Reading Terminal Market Corp., whom Mr. Holahan approached a decade ago to be the merchants' first general counsel. "He was a born leader, but not an over-the-top machismo leader."

Born in West Philadelphia, Mr. Holahan worked at the market for another vendor before opening his own stand. He was a foodie who helped raise the prowess of "locally grown," Cossrow said.

The Holahans opened a second store on Germantown Avenue in Chestnut Hill in late 2014.

"Coming to Chestnut Hill was an opportunity to build a business again somewhere special," Mr. Holahan told the Chestnut Hill Local at the time.

Mr. Holahan died after suffering a heart attack while walking home with his wife from Cossrow's house, his friend said.

"They were dropping off a pie dish," Cossrow said. "The last words he said to me were, 'Let's leave the women behind one night and get a drink. We need to talk about the market.' "

Mr. Holahan served as president of the merchants' association from 2007 to 2012. Before he officially took over, he dealt as interim president with one of the market's biggest controversies in recent memory: management's refusal to renew cheesesteak proprietor Rick Olivieri's lease.

"I think they're setting a dangerous precedent," Mr. Holahan said at the time. "It's not OK that a merchant has to go because the manager found someone with a prettier face. What happens after the next manager comes in?"

Mr. Holahan recently finished writing a book about indigenous Pennsylvania foods, Cossrow said, adding that Julie Holahan was figuring out what to do next with the manuscript.

Sarah Levitsky, Reading Terminal Market's marketing manager, said Mr. Holahan will be remembered for years to come at the 114-year-old food hub.

"He was a mentor to some of the younger vendors," Levitsky said. "Even after leaving as president, he continued to be a leader and a guiding force in this market."

In addition to his wife, Mr. Holahan is survived by sons William and James; daughter Isabella; his father, Joseph; his mother, Marie Louise Rice; two brothers; a sister; and nine stepbrothers and stepsisters.

A viewing will be held from 4 to 8 p.m. Wednesday, March 23, at Gloria Dei Church, 570 Welsh Rd., Huntingdon Valley. A celebration of life will be at 10 a.m. Thursday, March 24, at the church.

Note: This story has been updated to correct Mr. Holahan's age and his mother's name.