Keith L. Sachs, 72, whose business was running a corporation that distributed packaging for alcoholic beverages but whose life was with his wife, Katherine, exploring the endlessly fascinating and sometimes rugged terrain of contemporary art, died Monday morning, March 5, of pneumonia.

Mr. Sachs was a trustee of the Philadelphia Museum of Art since 1988, and is perhaps best known in recent years for a spectacular promised gift of 97 contemporary works of art that he and Katherine Sachs bestowed on the museum in 2014. The works represented nearly a half-century of looking at, thinking about, experiencing, and, ultimately, collecting art.

At the time of the announced gift, museum director Timothy Rub deemed it transformational, a point he reiterated Monday afternoon. The gift of works by Jasper Johns, Ellsworth Kelly, Charles Ray, Louise Bourgeois, and many others, Rub said, "was one of the most significant donations of modern and contemporary art ever to have come to the museum, comparable in scope and quality to the collections of Walter and Louise Arensberg and A.E. Gallatin."

Leslie Anne Miller, museum board chair, said Mr. Sachs "clearly understood the museum's need to grow in response to changing times" and acted on that knowledge.

"Keith was a change agent," she said.

"When we started to collect, we never thought of doing anything other than making a gift to some institution," Mr. Sachs said in a 2014 interview. "We never thought about investment value. … We care about Philadelphia. It's a wonderful city, and we've made a commitment to the arts along the way."

That commitment to art and love for the city led to the Sachs' bequest.

"It contains stellar works that reflect some of the most daring and productive directions in contemporary art over the past few decades, [and] it reflects a vision that is deeply personal and grounded in Keith and Kathy's heartfelt affection and admiration for the artists whose work they collect," Carlos Basualdo, museum curator of contemporary art, said at the time the museum mounted an exhibition of the works, "Embracing the Contemporary," in 2016.

Keith and Katherine Sachs were in every sense a team. They met at the University of Pennsylvania in the 1960s, where Mr. Sachs was a student at Wharton and Katherine Sachs was an undergraduate majoring in art history. When they were engaged, she gave him a print by Miro. They married in 1969.

In Boston, where Mr. Sachs attended Harvard Law School, they frequented a gallery on Newbury Street, occasionally buying a print – the only thing they could afford. Back in Philadelphia, where Katherine Sachs went to work in the communications department of the Art Museum, they frequented the Makler Gallery. Again, prints ruled.

With his brother Herbert, Mr. Sachs spent his workdays helping build the family packaging business into an international giant, Saxco International.

After Keith and Katherine Sachs' children were somewhat grown, the couple began venturing to New York City and buying there. What they acquired is what they liked; it was not driven by the idea of building a collection.

By the 1980s, they came to the realization that they needed to focus their collecting. Mark Rosenthal, a curator of modern art at the museum, helped them think through what they wanted to do.

They commissioned a site-specific work by Richard Serra, adorning their Rydal property with two massive and unnervingly tippy parallel walls of corten steel — Equal Elevations On and In (To Kathy and Keith) installed on the grounds.

Why Serra? In a 2014 interview, Mr. Sachs said that Serra "revolutionized sculpture."

"Before, you had sculpture which was on a pedestal, right?" Mr. Sachs continued. "You walked around it. You saw from here, you saw it from there. Period. With his work, you're in the space. You move through the space in time, right, and as you move, you cannot perceive the sculpture at any one point. You have to keep moving through it in order to grasp it. And when you're all finished, it's still very difficult to understand what the hell you've seen."

A wiry, unpretentious man with an acute analytical mind, Mr. Sachs was emotionally drawn to abstraction and minimalism, where he found passion.

Not surprisingly, over time, the couple's encounters with artists became increasingly important to both.

For instance, they first saw the work of English painter Howard Hodgkin in Pittsburgh in 1985. In 1988, they commissioned a double portrait from the artist. First they all had lunch in the Sachs' home. That was followed by dinner and lunch in New York and Philadelphia and London and Paris.

They dined and talked – and all the time, Hodgkin studied them. At one point, the artist asked them to switch places, mid-meal.

"One of the greatest lessons we both learned about art in general was the day we actually saw the picture for the first time, which was in 1991," Katherine Sachs recalled in a 2016 interview. "We learned very quickly that wonderful art, great art, is truly something that surprises you."

The painting, in an octagonal frame, features two swirls of bold brush strokes, one curling in green and orange, the other twirling in blue and white.

"I don't think it's representational," Mr. Sachs dryly allowed. "I think what he tried to do is convey the feelings he was feeling towards us and maybe the feelings we had for one another."

Katherine Sachs said, "I think it's a wonderful symbol for the [2016] exhibition. They decided that this exhibition should be called 'Embracing the Contemporary' because that title reflects our relationship with each other and our love of contemporary art. And I think this picture beautifully says that."

Mr. Sachs served as chair of the board of overseers at Penn's School of Design. At Penn, the couple endowed a contemporary art professorship, a position of visiting professor of fine arts at Penn Design, a guest curator program at the Institute of Contemporary Art, and the Sachs Fine Arts Program Fund. In 2016, they founded the Sachs Program for Arts Innovation with a gift to establish the Sachs Arts Innovation Hub at the Annenberg Center for the Performing Arts.

In addition to his wife and brother, Mr. Sachs is survived by a son, David, and daughters Deborah Rothman and Judy.

Funeral services are scheduled for 1 p.m. Thursday, March 8, at Joseph Levine & Sons Funeral Home, 4737 E. Street Rd., Trevose.