"It was constant work, not just to build something that might be good for 50 years, but also a little bit ahead of its time," said a son, Richard Powell.
Mr. Powell also gave generously. His donations exceeded $1 million to both the Museum of the American Revolution in Philadelphia and to Alfred University in western New York, his undergraduate alma mater. He also later served on the university's board.
"He was all about giving back," his son said. "That was as important to him as his career."
Mr. Powell was the son of Jewish Russian immigrants who arrived in New York City shortly after the turn of the century. He was the youngest of six children growing up on one floor of a three-story tenement in the 1920s.
Encouraged by his father, Mr. Powell went to college, studying engineering at Alfred and later earning a master's degree in industrial management at New York University. During World War II, he rose to the rank of captain in the Air Force.
Mr. Powell first worked as a consultant for sugar refineries, inventing systems to handle and move the product. He spent much of his time on the road and pocketed travel per diems to save money rather than travel home to New York.
His life changed when friends of his wife, Lea, arranged for him to meet Philadelphia real estate developer Morris Kravitz. Mr. Powell sat in on a partners' meeting at Kravitz's firm and listened to them discuss development of the Huntingdon Valley Shopping Center. Mr. Powell, feeling he could assist with management of the project, eventually pitched a job for himself to Kravitz, who hired him.
Mr. Powell, then 35, was soon overseeing construction projects and managing tenants for the firm. The Powell family moved to Levittown, in Bucks County, in 1956 and in 1970 to Valley Forge.
Kravitz eventually turned the company over to Mr. Powell and Schaeffer, who built the company with the help of partners and consultants, Mr. Powell's son said. Part of their vision was to adjust the shopping centers to fit the preferences of the communities in which they resided. In 1981, for instance, they rebranded and expanded the King of Prussia mall, bringing in more upscale stores such as Bloomingdale's.
"The key was to put as many department stores as you could, and the right kind of department stores, at the confluence of these highways," Richard Powell said.
Mr. Powell and Schaeffer stepped down from their roles in the company in 1995.
Mr. Powell's many charitable endeavors included his temple, Brith Achim, in King of Prussia, and the King of Prussia Rotary. When he was president of the club in the 1970s he gave a distant relative a job at Kravco so the relative and his family could flee Argentina, which was unstable at the time.
"It was very difficult to get a visa," Ernest Zlotolow said. "So he gave me a job and put us up in his house for a full month so we could get our bearings."
Mr. Powell also was dedicated to his family, which included four children and 13 grandchildren.
"He basically was the problem-solver," his son said. "If the family had any problems, we'd come to him. For him, it was family, business, and philanthropy."
His wife died in 2005. Surviving are sons Richard and Jon, daughters Carol and Nancy, 13 grandchildren, and eight great-grandchildren.
Services were Monday, June 9, at Temple Brith Achim in King of Prussia, with interment at Haym Salomon Memorial Park in Malvern.
Contributions may be made to the Powell Religious School at Temple Brith Achim, the Einstein Medical Center Montgomery neonatal unit, or a charity of the donor's choice.