"Most of the time he didn't think about legacy," he said. "He was pretty much in the moment."
But Newman, who died Friday of cancer at age 83, told the men he wanted to be remembered for the "Hole in the Wall" camps he helped to start across the world for children with life-threatening illnesses and to make sure that 100 percent of the profits from his popular food company, Newman's Own, would continue to benefit such camps and thousands of other charities.
Horvitz is chairman of the Association of Hole in the Wall Camps, which has 11 camps across the globe. Newman told him that he had been lucky in life, born with piercing blue eyes and gift for acting, and how it was unfair that so many innocent children were unlucky to have been burdened with devastating diseases such as AIDS or leukemia.
"He felt a need and an obligation to try to give back," Horvitz said.
"He loved the camps. He loved being there. He loved being with the kids," he added. "He loved their smiles and their laughter."
In 1982, Newman and writer A.E. Hotchner started Newman's Own to market Newman's original oil-and-vinegar dressing. It began as a joke and grew into a multimillion-dollar business.
Newman and his food company have given more than $250 million to charity over the years. Last year, $28 million from the sale of pasta sauces, salad dressings, popcorn and other products was distributed to a variety of social causes, including the Safe Water Network, which Newman helped start to provide safe drinking water to impoverished communities in places like India and Africa.
Until two years ago, Newman had the task of personally distributing the company's profits. But he and Forrester set up a private, independent foundation, known as Newman's Own Foundation, to carry on the work without Newman.
"Really, everything is in great shape," Forrester said of the foundation and the company after Newman's death.
"He said, 'When I'm not here, this foundation is to continue the tradition of giving all of this money away,"' said Forrester, the foundation's vice chairman.
Forrester joked how such planning wasn't part of Newman's nature. A sign famously hangs in Newman's Westport, Conn., offices that reads, "If I had a plan I would be screwed."
Newman welcomed the opinions of others as he pursued the business and his philanthropic efforts. Forrester explained how the actor believed in the benefit of "creative chaos," where, as in a movie set, different people offer ideas about how a scene should be handled.
"That was Paul's enduring philosophy, and it worked," Forrester said. "It sounds awful, but it was part of Paul saying everybody had a voice."
At Forrester's request, Newman came up with what he wanted the Newman's Own company - he hated the word "brand" - to stand for. Newman listed quality food, fair labor practices, a mission focused on philanthropy and not profit, and an open environment in the workplace, not a bureaucratic one.
Forrester said that mission will continue, even though Newman is gone.
Also, his smiling face will still appear on bottles of marinade and boxes of frozen pizza, and his wife, actress Joanne Woodward, will still sit on the Newman's Own Foundation Board of Directors. Newman typically sat in on all the board meetings, with the exception of the most recent one, about a week ago.
Forrester said Newman's friends at Newman's Own - some who have worked there from the early days of the company - plan to look for ways to expand the business in order to carry out the actor's wishes and give away even more money.
"We're stewards of this legacy," he said.