William Irwin Schaffer
c. 1919 photograph
|Chief Justice of the Supreme Court of Pennsylvania|
January 2, 1940 – January 4, 1943
|Preceded by||John W. Kephart|
|Succeeded by||George W. Maxey|
|Associate Justice of the Supreme Court of Pennsylvania|
December 14, 1920 – January 2, 1940
|Attorney General of Pennsylvania|
January 21, 1919 – December 14, 1920
|Governor||William Cameron Sproul|
|Preceded by||Francis Shunk Brown|
|Succeeded by||George E. Alter|
|Born||February 11, 1867|
|Died||January 15, 1953 (aged 85)|
Belleair, Pinellas County, Florida
|Spouse(s)||Susan Ashley Cross|
William Irwin Schaffer (February 11, 1867 – January 15, 1953) was a Pennsylvania lawyer and judge. He served briefly as the state's Attorney General, resigning to serve on the state's Supreme Court for over twenty years, including three years as Chief Justice.
Schaffer was the son of George Alfred and Mary Henrietta Irwin Schaffer. His maternal grandfather, William H. Irwin, had served as Adjutant General of the state. Schaffer grew up in Chester, Pennsylvania. He left school at age fifteen, finding odd jobs, ending up as an assistant in a law office, where he learned law. He was admitted to the bar of Delaware County in 1888 on his 21st birthday, the legal minimum.  
He served two terms as District Attorney for Delaware County. He was active in Republican politics, and was appointed by Governor William Cameron Sproul, first to Attorney General, and then to fill a vacancy on the state Supreme Court. He then won election to a 21-year term on the Court. He was elevated to Chief Justice based on seniority in 1940. 
Schaffer was identified, along with Justice John W. Kephart, in a Senate Banking Committee investigation, as being on a J. P. Morgan "preferred" list, allowing them steeply discounted prices for the purchase of certain securities. Governor Pinchot asked the two justices to resign. The judges denied any impropriety.  
- Wiley 1894, pp. 316–18.
- Joyce 1919, pp. 589–91.
- "Justice Schaffer of Pennsylvania". The New York Times. January 16, 1953. p. 23.
- "Ban on Sunday Baseball is Upheld". The Pittsburgh Press. June 25, 1927. p. 1.
- "Gov. Pinchot asks judges who took favors to resign". The Christian Science Monitor. May 29, 1933. p. 6.
- Davies, Lawrence E. (June 4, 1933). "Democrats back Pinchot's attack". The New York Times. p. E1.
- Joyce, J. St. George (1919). Story of Philadelphia. Philadelphia: Harry B. Joseph.
- Wiley, Samuel T. (1894). Biographical and Historical Cyclopedia of Delaware County, Pennsylvania. Delaware County: Gresham Publishing Company.
- Smull, John A. (1920). Smull's Legislative Hand Book and Manual of the State of Pennsylvania. Harrisburg Publishing Co.
Francis Shunk Brown
Attorney General of Pennsylvania
George E. Alter
John W. Kephart
Chief Justice of the Pennsylvania Supreme Court
George W. Maxey