Rob Mayer enjoyed the company of senior citizens.

He loved his elderly grandparents. And when his parents traveled, he followed the family’s European butler and cook around the Mayers’ Winnetka home, listening to their stories and wisdom.

His great-uncle and great-aunt, Maurice L. and Hulda Rothschild, owned Rothschild’s clothing stores. Upon her death, Hulda Rothschild requested that Mr. Mayer oversee the funds the couple designated for charity.

He established a foundation that dispensed grants and funded research and conferences on enhancing the lives of the elderly by ensuring they were comfortable — whether in their own houses or in long-term care facilities.

Under his leadership for the past 25 years, the Hulda B. and Maurice L. Rothschild Foundation worked with architects on innovative design, promoted homelike settings in residential communities, and advocated with the Center for Medicare & Medicaid Services. The foundation also convened regulatory task forces that brought together government officials, designers and nursing-home companies.

“He was a passionate advocate for older adults to be able to live their lives with dignity and autonomy,” said Nancy Zweibel, senior program officer for The Retirement Research Foundation in Chicago.

Mr. Mayer believed that little things could do a lot to boost independence. Instead of nursing homes with shared rooms and institutional furniture, the foundation advocated for private rooms decorated by residents, with their own stoves.

He “has [been] the catalyst and force behind the most significant and meaningful regulatory changes in nursing homes in the last decade,” said Bonnie K. Burman, director of the Ohio Department of Aging. “Most significant among these are the Life Safety Code changes to create more homelike environments in long-term care settings and the new person-centered food and dining standards developed for nursing homes.”

In 2012, Healthcare Design Magazine called him one of the most influential people in the industry.

“He basically applied venture capitalism to philanthropy,” said his wife of 39 years, Dr. Debra E. Weese-Mayer. “Despite being born into privilege, he understood his responsibility was to make the world a better place.”

Mr. Mayer, 66, died Thursday at Northwestern Memorial Hospital of bile duct cancer of the liver.

He grew up in Winnetka, a grandson of Nathan Cummings, who founded Consolidated Foods, which grew to include Sara Lee Kitchens, Ball Park Franks, Jimmy Dean Sausages, Hillshire Farm and Kiwi Shoe Polish. Nathan Cummings once took Rob Mayer and his other grandchildren to Israel and introduced them to Prime Minister Golda Meir. Rob Mayer’s father, Bob, was president of Rothschild’s department stores.

He went to religious school at North Shore Congregation Israel with his friend, Jim Weese. When he was 13, Rob met Jim’s little sister, Debra Weese, who would later become his wife.

He attended North Shore Country Day School, worked in the mailroom at Sara Lee, and achieved the rank of Eagle Scout.

A summer program at The Citadel, South Carolina’s military college, kindled an interest in the Civil War. He collected ceremonial Civil War swords.

Sweet-natured and unpretentious, “he had friends all over the world” from being a ham radio operator, and he also became manager of the radio station at Kenyon College, said his daughter, Jaimie Ariel Mayer.

He earned a bachelor’s degree at Kenyon College, an MBA at the University of Chicago, and a PhD from Northwestern University’s Kellogg School of Management.

Before creating the Rothschild foundation, he founded a healthcare company for the elderly and disabled, HomeCorps.

When his children were small, he used their puppet, Wolfie, and their stuffed animals Possum, Possie and Valentine, to entrance them with his bedtime yarns about “Bat Puss and Robin.”

Mr. Mayer underwent a triple bypass in his 40s and a quadruple bypass nine years later. He remained an energetic dad who enjoyed planning family vacations, including trips to the Galapagos and Falkland Islands; Cambodia, China, Japan and Vietnam, and New Zealand and Australia. They also went on safaris in Africa.

He dove into local experiences, including street food. “In Cambodia, there were crispy tarantulas” he bought for his children to try, Jaimie Mayer said.

He enjoyed dim sum in Chinatown, Tom Clancy novels, and silly movies like “Naked Gun.”

Mr. Mayer is also survived by his mother, Beatrice “Buddy” Mayer, another daughter, Jennifer Mayer; a son, Jonathan Mayer; a sister, Ruth Durchslag; his mother-in-law, Florence K. Weese, and his brothers-in-law, Dr. Jim and Dr. Bill Weese.

Services have been held. Because of the family links to Rothschild’s, he was always nattily dressed, even in his casket. His family also tucked in his safari clothes; a Batman robe to represent his “Bat Puss” stories, and comfy Hush Puppy shoes.

For shiva information, contact CelebratingRobsLife@gmail.com.