John William Ditter Sr. was born in Philadelphia, Pennsylvania on September 5, 1888. He graduated from the Temple University School of Law in Philadelphia in 1913. He worked as a professor of history and commerce in Philadelphia high schools from 1912 to 1925. In 1925 he moved to Ambler, Pennsylvania, and commenced the practice of law. He served as workmen's compensation referee for eastern Pennsylvania in 1929.
Ditter was elected as a Republican to the Seventy-third from the 17th District of Pennsylvania and to the five succeeding Congresses. During his years in Washington, Ditter served on the House Committee on Appropriations. He also was a member of the subcommittee on Navy Department appropriation bills, and at the time of his death was ranking minority member. He served until his death in an airplane crash near Columbia, Pennsylvania. He is buried in Whitemarsh Memorial Cemetery in Prospectville, Pennsylvania.
His son, John William Ditter Jr. was a federal judge, serving on the United States District Court for the Eastern District of Pennsylvania.
