William (Mac) MacClarence, a man of principle, infinite curiosity and joy, a die-hard optimist and lover of history and all things chocolate, died peacefully at his home in Naples, Fla. on Oct. 3. He was 100 years old.

He was born in Oak Park, Ill., the youngest of three children born to immigrant parents from Ireland and Scotland who had met in Brooklyn. The family moved to Baltimore when he was in elementary school. He attended Baltimore Polytech and entered the school of engineering at Columbia College in 1941.

The attack on Pearl Harbor and the U.S. entry into World War II led him and many of his friends to enlist in military service. He joined the Army Air Corps and qualified as a fighter pilot. He was sent to Fowlmere, England, where he joined the 339th Fighter Group. He flew P-51 Mustang aircraft as a bomber escort and was engaged in ground strafing in the European theater. Among other honors, he was awarded a Distinguished Flying Cross and an Air Medal with 11 oak clusters.

He returned to the United States and resumed his studies at Columbia, graduating with an engineering degree in 1948.

Mac worked at General Foods for 35 years, progressing through many companies and positions within the corporation at the national and international levels. Following completion of his studies in the advanced management program of Harvard Business School in 1969, he moved into product development and marketing.

He moved to Caracas in Venezuela as president of La India, a company that produced chocolates and marketed General Foods products in South America. He then worked with Gevalia, a Swedish company, to pioneer direct marketing for General Foods.

After retiring MacClarence consulted with P.J. Carroll & Company in Ireland to develop the market in Europe for salmon farmed off the Irish coast and to create a direct marketing strategy for salmon and other Irish products. He was respected as an important mentor by many aspiring leaders.

Mac was an active outdoorsman. He loved to ski, boat, fish, bike and, upon retirement, garden. He encouraged and supported his children and all those he mentored to pursue with a passion, their own activities, interests and dreams.

He met and married Patricia (Toni) Dougherty, his wife of 64 years, while completing his studies at Columbia. They began their family in New York, relocating many times over the years during his career. He referred to Toni as his “guide through life” as she made a home and comfortable life for him and their family following each of his transfers. Toni predeceased him in 2011.

In 1984, Mac and Toni arrived as seasonal Vineyard residents as a result of Toni’s search for a place where grandchildren could gather. Mac and his dog Murray were fixtures around Edgartown and Mac rode his bike around the Katama loop well into his 90s. He was a member of the Edgartown Yacht Club and Edgartown Golf Club, and loved going to the golf club in the afternoon to play a few holes. He loved to fish and was a frequent derby participant.

Mac always expressed that living on the Vineyard was like living in a national park and people should treat it as the special place it is.

He is survived by his daughters, Michael Bashford and her husband James, Patricia and her husband Allen Harden, and Kathleen Rudkin; his son Thomas and his wife Meg; and 10 grandchildren and nine great-grandchildren.