Samuel Alexander “Sam” Cooke, co-founder of the Manoa Heritage Center, a philanthropist and descendant of one of Hawaii’s prominent kamaaina families, died in his sleep Wednesday night. He was 78.

Cooke, a graduate of Punahou School and Cornell University, served on numerous foundation boards and retired as senior vice president of Morgan Stanley in 2002, where he was a financial adviser to public, private and nonprofit corporations.

A generous benefactor and a mentor to many, Cooke contributed more than 50 years of community service during his lifetime, with a particular passion for conservation, the natural and cultural history of the Hawaiian Islands, fine arts and community.

“I think Sam’s civic legacy in Hawaii is unsurpassed,” said Kelvin Taketa, president and CEO of the Hawaii Community Foundation. “We are all very sad to have lost someone who we think of as a giant in our community.”

Cooke was founding chairman of the Board of Governors for the Nature Conservancy of Hawaii as well as chairman of what was then the Honolulu Academy of Arts (now the Honolulu Museum of Art), founded by his great- grandmother Anna Rice Cooke. He was also chairman of the Hawaii Community Foundation.

“If you look at those three civic institutions, Sam is the common denominator,” said Taketa, who knew Cooke for 35 years, beginning with his time at the Nature Conservancy. “I learned many things from him, not the least of which was the fact that when Sam said he was going to get something done, he got it done, and he always did it with grace and good humor.”

Born in Honolulu, Cooke grew up on both Oahu and Molokai. Manoa was his last beloved home. He was a descendant of Amos Starr Cooke and Juliette Montague, who arrived in Hawaii with the eighth company of missionaries in 1837.

He and his wife, Mary Moragne Cooke, founded the Manoa Heritage Center in 1996 to promote stewardship of the natural and cultural heritage of Hawaii. They restored the historic home Kuali‘i, which was built by Cooke’s grandparents, as well as the Kuka‘o‘o Heiau, believed to be the only remaining one intact in the ahupuaa of Waikiki.

The center offers guided tours of its garden on 3.5 acres, filled with native Hawaiian plants, as well as the heiau, to schools and to the public, by appointment.

At the Nature Conservancy, Cooke directed campaigns that raised at least $15 million to protect more than 50,000 acres of key conservation lands, including the Moomomi shoreline and mauka watershed on Molokai, where he spent time as a youth. He eventually served on the Conservancy’s international board, as well, and played a role in securing additional funds for the organization in Hawaii.

Carol Fox, director of special projects at the East-West Center, remembers him fondly from when she worked with him at the Nature Conservancy.

She called him a great mentor to many and considers herself lucky to have been one of those he mentored.

“He was a generous visionary who helped so many without expectation of acknowledgment and return,” she said. “That’s why he was such a great role model. I feel as if his passing is the end of an era, and it leaves a major hole in the heart of Hawaii.”

Both Taketa and Fox remember Cooke’s gift for telling stories, especially of his days on Molokai. His leadership style was a combination of respect and humor, along with a shrewd view of economic realities. Taketa remembers that at Conservancy board meetings, he would pull out his gold pocket watch to ensure that meetings started and ended on time.

He enjoyed collecting Hawaii art as well as Pacific navigation books, and loved people. He was named Historic Hawai‘i Foundation Kama‘aina of the Year in 2006 and also Outstanding Philanthropist of Hawaii, among numerous other recognitions.

Cooke is survived by wife Mary Cooke; daughters Juliette, Catherine and Edith; and grandchildren Sam and Zoe.

A celebration of life for Cooke will be held 4 p.m. Jan. 16 at the Central Union Church main sanctuary, 1660 S. Beretania St., followed by a reception at 5 p.m. in the parish hall. In lieu of flowers, the family welcomes donations to the Manoa Heritage Center, 2859 Manoa Road, Honolulu 96822.