John E. Cassidy, Jr. (July 22, 1924 — June 25, 2003) was a Democratic member of the Illinois House of Representatives.
He served during World War II in the Pacific Theater.
[3] In 1964, he was elected to the Illinois House of Representatives and served for two terms.
[3] In the 1986 general election, Cassidy ran against Republican candidate and member of the Illinois House of Representatives Carl Hawkinson.
Despite the hope of Democrats to capitalize on cross preasure of party affiliation and a hometown state senator to break the Republican hold on the "Peoria seat", Hawkinson won the general election.