Joseph Sill Clark, Jr. (October 21, 1901–January 12, 1990) was an American lawyer and politician in the mid-20th century. He served as the mayor of Philadelphia (1953–1957) and U.S. senator from Pennsylvania (1957-1969).

Clark began his career as a lawyer in Philadelphia. In 1941, he was called up to military service for World War II, eventually becoming a colonel in the United States Army Air Force before mustering out in 1945. (Clark won the Bronze Star, the Legion of Merit, and the OBE for his wartime service in the China-Burma-India theater .)

After the war, Clark became involved in Philadelphia city politics, first winning the city controller position in 1949, then moving up to mayor three years later. On the strength of his mayoral record, he won the Democratic nomination for the U.S. Senate in 1956, and went on to beat incumbent James H. Duff in the general election.

After losing the 1968 senatorial election to Republican Richard Schweiker, Clark retired from politics, and lived the rest of his life in Philadelphia.

Clark was a native of Philadelphia. He received his bachelor's degree magna cum laude from Harvard University in 1923 and his law degree from the University of Pennsylvania in 1926. He was a fellow of the American Academy of Arts and Sciences and a member of the American Philosophical Society.

|- style="text-align: center;" | width="30%" |Preceded by:
James H. Duff | width="40%" style="text-align: center;" |U.S. Senator from Pennsylvania
1957–1969 | width="30%" |Succeeded by:
Richard S. Schweiker

Writings

• The Senate Establishment (1963)
• Congress: The Sapless Branch (1964)

References

• Who's Who in America. Chicago : Marquis, 1984.
• Biographical Directory of the United States Congress: CLARK, Joseph Sill