William Rotch Wister Jr., 86, of Palm Beach, Fla., a lawyer and a descendant of a family that came to Philadelphia in the 18th century and built the Germantown mansion Grumblethorpe, died Saturday, Nov. 23, of a heart ailment at Christiana Hospital in Newark, Del.

Mr. Wister was descended from Caspar Wistar, a German glassmaker who arrived in Pennsylvania in 1717. Caspar’s brother John arrived a decade later and changed the spelling of the family surname from Wistar to Wister.

Mr. Wister was the son of Frances Stotesbury Mitchell and William Rotch Wister. On the paternal side, his great-great-grandmother was the noted English actress Fanny Kemble, who in 1849 divorced her husband, Pierce Butler Jr., a slave owner from South Carolina, to become a crusading abolitionist.

His grandfather Owen Wister was a college classmate and close friend of President Theodore Roosevelt. He was the author of several books, most famously the 1904 work The Virginian, a depiction of the Old West.

On the maternal side, Mr. Wister’s ancestors included William White, the first presiding bishop of the Episcopal Church; Silas Weir Mitchell, a physician who pioneered the rest cure; and Edward T. Stotesbury, a senior partner in Drexel & Co. for 30 years.

Grumblethorpe was the home of the Wister family for 160 years. It was built in 1744 as a summer residence so the family could escape the yellow fever that plagued what is now Center City. In 1793, the house and gardens became the family’s year-round residence. It’s now a museum, part of the Colonial Germantown Historic District.

Wister Street in Philadelphia bears the family’s name. It runs east from Germantown Avenue in Germantown and turns northward to 66th Avenue in Olney, where it ends.

In April 2012, the Wister name surfaced when the family made available for sale at Freeman’s 92 lots of estate items. These included three Wister family silhouettes that were formerly kept at Grumblethorpe and a signed autograph letter from President George Washington dated Philadelphia, Jan. 7, 1795.

Despite his venerable lineage, "he was humble,” said his wife, Diana Dorrance Strawbridge Wister.

Born in New York City, Mr. Wister graduated from St. Paul’s School in Concord, N.H., Harvard University, and the University of Pennsylvania Law School.

He served in Army Intelligence and then worked as a special assistant to the director of the Peace Corps before practicing law in Philadelphia for several years.

Finding the law not to his taste, he became a senior vice president and member of the executive committee of Janney Montgomery Scott, an investment adviser and wealth management firm in Philadelphia. He retired in the 1990s.

He served on many charitable and corporate boards, including those of Lankenau Medical Center and the Brandywine Conservancy and Museum of Art. He was the conservancy’s board president for a time and was a board member for 21 years.

“He had a keen interest in the history and land conservation work of Brandywine and was instrumental to our success in many ways,” said Virginia A. Logan, Brandywine’s Frolic Weymouth executive director and CEO. “We remain truly grateful for his support."

In 1966, he married Ethel Pew Benson, known as “Peppi.” The couple raised four children in Berwyn. They divorced in the early 1990s. In 1994, he married Diana Strawbridge. They lived in Palm Beach.

He vacationed every summer at his home in Northeast Harbor, Maine., where he enjoyed spending time with family. He was an accomplished duplicate bridge player. He played tennis and golf into his 80s and won many trophies.

Both his wife and former wife survive. In addition, he is survived by children, Effie, Sabina, Noli, and Will; four grandchildren; and a sister.

Services and burial are private.

Memorial contributions may be made to the Brandywine Conservancy, P.O. Box 141, Route 1, Chadds Ford, Pa. 19317, or the Neighborhood House, 1 Kimball Rd., Northeast Harbor, Maine 04662.