Peter E. Haas Sr., who helped build the Levi Strauss empire, was known for his modest, understated leadership style and generosity to San Francisco institutions and its Jewish community.

He died Saturday, Dec. 3 at home in San Francisco. He was 86.

“Most people think of leaders as pretty smart people who are aggressive, cocky, self-confident blusterers, who are didactic and not democratic,” said Haas’ lifelong friend Warren Hellman. “But he was the opposite of all those things. He was a highly moral and ethical person with tremendous integrity. He never cheated or cut corners.”

Phyllis Cook, executive director of the Jewish Community Endowment Fund of the S.F.-based Jewish Community Federation, observed Haas’ leadership style over the years from her vantage point as both a lay leader and a professional.

“He took time to lend serious reflection and time to work actively with diverse boards over a long period of time,” she said, noting he had been at two recent meetings at the federation. “He brought fairness, balance and judgment, often proving to be the decisive voice in the process.”

Haas was born in 1918 in San Francisco, to Elise Stern Haas and Walter A. Haas Sr.

His family was more philanthropic than religious. When he was interviewed as part of the JCF Oral History Project at U.C. Berkeley, he said that he never had a formal Jewish education, nor a bar mitzvah. Rather, his family expressed its Judaism through tzedakah.

“It had come from my forebears,” he said. “It was part of my father and mother … They were both very much involved in philanthropy and helping in the community. That was rather an inheritance, I guess.”

When asked once why his family was so generous, he said, “If we had money … it was really not ours alone. It was our obligation to use it wisely to help others.”

Haas graduated from U.C. Berkeley in 1940 and from Harvard Business School in 1943 as a Baker Scholar.

At first, he resisted joining the family business and took a job with an aircraft-defense contractor.

His job there allowed him to get firsthand knowledge of the conditions of blue collar workers, an insight that influenced his managerial style throughout his long career. It also influenced the way he gave, as he supported numerous charities that helped poor families.

He joined his brother, the late Walter Haas Jr., at Levi Strauss & Co. in 1945, working his way up the ladder. His great-great-uncle, a Bavarian immigrant named Levi Strauss had begun the company as a Western outfitter in 1853. By the time he left it to his four nephews, it had become a very successful manufacturing and dry goods business. But it was Haas and his brother who have largely been credited for the popularity of Levi’s specifically, and making blue jeans a fashion statement around the world.

In the pre-segregation South of the 1950s, Peter Haas insisted that Levi Strauss only open factories there if black workers were treated equally.

Haas served as executive vice president of the company from 1958 to 1970, president and chief executive until 1981 and chair from then until 1989, after which he became chair of the executive committee. He continued to work there until his death, even after a stroke confined him to a wheelchair some years ago.

Haas took the same kind of leadership he used in the corporate world and applied it in a number of leadership positions in the nonprofit world as well.

Not only did he give millions of dollars toward higher education, especially to his alma mater, U.C. Berkeley, as evident by the Haas School of Business and Haas Pavilion, but also served as a trustee of the university. He also gave generously to Stanford University.

He served as chairman of the United Way, and then, from 1977 to 1978, as president of the JCF.

“With all of his voluntary activities and public activities with Stanford and Cal, being head of the federation was very significant and emotional for him,” said Rabbi Brian Lurie, the federation’s executive director at the time.

“His father had been president of the federation, and he was following in his father’s footsteps and that was enormously important to him.”

Like most of San Francisco’s Jewish leadership in those days, Haas did not support Jewish day schools. “I was quite lukewarm about [them],” he told U.C. Berkeley’s Oral History Project. “I guess I feel much more that we should be a part of the community.” But the federation began supporting them under his leadership anyway, because “that’s the will of the community.”

In 1994 he served as chair of the JCF’s Endowment Fund, and over the years had many roles at the federation.

In 2002, the federation bestowed its Robert Sinton Extraordinary Leader of the Year award to Haas.

Cook said that his style was to let everyone speak, and then ask a question, or make a statement that would push the decision forward. “He was very fair,” she said. “The Jewish community is at its strongest when its best leaders are clear about their Jewish identity and their responsibilities. Peter Haas was such a leader.”

Haas also served on the board of the Jewish Community Center of San Francisco. In fact, said Nate Levine, the center’s executive director, Haas told Levine that the then-San Francisco JCC was the first board he had ever served on and that started his career in public service.

When fund-raising began for the new JCC, Levine said, Haas took a leadership role by giving generously — and early — “and that set the pace for others.” Haas was one of the new JCC’s top donors.

“It was always a special delight to see him at programs at the new JCC,” said Levine. “It was great that he was able to see what he and his family were able to help build.”

Haas was also deeply involved with the Skirball Cultural Center in Los Angeles, serving on the Jewish museum’s board of trustees and donating significant funds.

“During the past decade as a member of the board, Peter helped refine the Skirball Cultural Center’s mission and guided the center’s growth as a cultural and educational institution into the largest of its kind in the world,” said Uri Herscher, Skirball’s president and CEO.

Both Haas and his wife, Mimi, served in leadership positions with the San Francisco Museum of Modern Art and the New York Museum of Modern Art.

Before Haas’ stroke, he was an avid horseback rider. He also never missed a Cal game, either basketball or football, and a special platform was even built for him in Haas Pavilion to accommodate his wheelchair. In fact, he was getting ready to go to a game Saturday evening, Dec. 3, when his breathing became irregular, and he died.

Hellman, of San Francisco, said that if Haas got involved with an organization, he usually ended up running it.

Furthermore, “If he asked you to do something for one of his causes, you’d always end up doing a whole lot more.”

Haas’s first marriage to Josephine Baum ended in divorce. He is survived by his wife, Mimi Lurie Haas; son Peter E. Jr., of Novato; daughter Margaret Haas of Ross; two stepsons, Daniel and Ari Lurie of San Francisco; four grandchildren and one great-grandchild.

Donations can be made to the San Francisco Museum of Modern Art, 151 Third St., S.F., CA 94103; the Child Care Facilities Fund of the Low Income Investment Fund, 100 Pine St., Suite 1800, San Francisco, CA 94111 or the Athletic Study Center, U.C. Berkeley Foundation, University Relations, 2080 Addison St., Berkeley, CA 94720.