|Intro||US tennis player|
|Countries||United States of America|
|Birth||30 November 1861 (Germantown, Philadelphia, Philadelphia County, Pennsylvania)|
|Death||14 April 1956 (Chestnut Hill, Philadelphia, Philadelphia County, Pennsylvania)|
Joseph Sill Clark Sr. (November 30, 1861 – April 14, 1956) was a champion American tennis player. Clark won the 1885 U.S. National Championship in doubles, partnering with Dick Sears. He was also the inaugural singles and doubles national collegiate champion, in 1883. When he died in 1956 he was Philadelphia's oldest practicing attorney.
Clark was born in Germantown, Philadelphia, Pennsylvania, on November 30, 1861, to a family of bankers and financiers. His father, Edward White Clark, was a partner in the family firm, E. W. Clark & Co.. Clark's brother, Clarence Munroe Clark, would also become a tennis player of note.
As a student at Harvard University, Joseph Clark won the U.S. intercollegiate singles and doubles titles in its inaugural staging, in the spring of 1883. In the singles, he defeated fellow Crimson player Dick Sears.
Clark graduated Harvard in 1883 and later earned a law degree. He and his brother, Percy Hamilton Clark, opened a law practice together at 321 Chestnut Street in Philadelphia. The practice centered on the "street railway, electric light, and power businesses" operated by E. W. Clark & Co., his family's financial firm.
In 1885, he took the U.S. National lawn tennis doubles title, and also became champion of Canada, the first American to be so. Clark was also a three-time semi-finalist at the U.S. National Championships lawn tennis singles in 1885, 1886 and 1887. He captured the first two U.S. National mixed doubles championships in 1888 and 1889, partnering with Marian Wright.
He served as president of the United States National Lawn Tennis Association from 1889 until 1891.
On November 26, 1896, Clark married Kate Richardson Avery (1868-1951), whose family owned Avery Island in Louisiana. She was the daughter of Dudley Avery (1810-1879), who was the brother-in-law of Tabasco sauce inventor Edmund McIlhenny (1815-1890).
Their children included two sons: future Philadelphia mayor and U.S. Senator Joseph Sill Clark Jr. and Avery B. Clark. They had at least three grandchildren: Joseph Jr.'s children Joseph S. Clark III and Noel (née Clark) Miller, and Avery's daughter Kate Avery Clark.
In 1955, Clark was inaugurated into the International Tennis Hall of Fame.
Clark died April 14, 1956, in Chestnut Hill, Philadelphia, Pennsylvania.