When Mayor Bill Green needed a prominent figure to chair the Century IV Committee, planning the Bicentennial of Philadelphia, he chose Mr. Boothby.
There was a reason people turned to him, his son said: "Any one who worked with my father, or knew him, would tell you that he was the kindest, nicest man they ever met, and a true gentleman."
Although he spent time in the public arena, he was happiest when surrounded by family, his son said.
Mr. Boothby graduated from the William Penn Charter School in 1939, and served two years in the Army, ending in 1944. He went on to receive a bachelor of science degree in engineering from Lehigh University in 1946. He did graduate work at the University of Pennsylvania Wharton School in finance and commerce.
He joined Eastman Dillon in Philadelphia in 1950, became resident partner in Philadelphia in the 1950s, and joined the firm's New York office in 1964.
Mr. Boothby was appointed chief executive partner in 1970, and he rose to managing director in 1980 of what was then called Paine Webber.
The firm was acquired by the Swiss bank UBS AG in 2000. Mr. Boothby helped pave the way for the change.
Mr. Boothby was also trustee of the Glenmede Trust from 1988 through 2010. He served on the boards of many major corporations, including Getty Oil, Sperry Rand, Food Fair, INA, and Georgia-Pacific.
He was a board member of the Philadelphia Orchestra, and Morris Arboretum, and a trustee of Springside School, Episcopal Hospital, Academy of Natural Sciences, and William Penn Charter School.
He was a member of the Philadelphia Club, the Philadelphia Cricket Club, the Racket Club of Philadelphia, and the Gulph Mills Club.
His hobbies included travel, golf, and attending Philadelphia Eagles games, which he had done since 1960.
Besides his son, he is survived by his wife, the former Florence Clifford; another son, Willard S. III; daughter Ann Boothby LeBreton; eight grandchildren; and three great-grandchildren.
A memorial service will be held at 11:30 a.m. Saturday, May 17, at St. Paul's Episcopal Church, 22 E. Chestnut Hill Ave., Philadelphia. Interment was earlier.
Donations may be made to the Academy of Music in Philadelphia by linking to: http://www.academyofmusic.org/home.php.