John William Rainey was a U.S. Representative

United States House of Representatives

The United States House of Representatives is one of the two Houses of the United States Congress, the bicameral legislature which also includes the Senate.The composition and powers of the House are established in Article One of the Constitution...

 from Illinois

Illinois

Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

.

Born in Chicago, Illinois, Rainey attended the public schools of his native city, De La Salle Institute

De La Salle Institute

De La Salle Institute is a Catholic, Lasallian, secondary school located in the Bronzeville neighborhood on the South Side of Chicago, Illinois. The school is currently housed on two separate campuses. The original school, now called the Institute Campus is for men...

, and the Kent College of Law.
He was admitted to the bar

Admission to the bar in the United States

In the United States, admission to the bar is the granting of permission by a particular court system to a lawyer to practice law in that system. Each U.S. state and similar jurisdiction has its own court system and sets its own rules for bar admission , which can lead to different admission...

 in 1910 and commenced the practice of law in Chicago.
He served as assistant judge of the probate court of Cook County 1910-1912.
He served as clerk of the circuit court 1912-1916.

Rainey was elected as a Democrat

Democratic Party (United States)

The Democratic Party is one of two major contemporary political parties in the United States, along with the Republican Party. The party's socially liberal and progressive platform is largely considered center-left in the U.S. political spectrum. The party has the lengthiest record of continuous...

 to the Sixty-fifth

65th United States Congress

The Sixty-fifth United States Congress was a meeting of the legislative branch of the United States federal government, composed of the United States Senate and the United States House of Representatives. It met in Washington, DC from March 4, 1917 to March 4, 1919, during the fourth and fifth...

 Congress to fill the vacancy caused by the death of Charles Martin

Charles Martin

Charles Martin is a poet, critic and translator. He grew up in the Bronx. He graduated from Fordham University and received his Ph.D. from the University at Buffalo, The State University of New York. He now teaches at the City University of New York, Syracuse University, and the . Martin's...

.
He was reelected to the Sixty-sixth

66th United States Congress

The Sixty-sixth United States Congress was a meeting of the legislative branch of the United States federal government, comprising the United States Senate and the United States House of Representatives. It met in Washington, DC from March 4, 1919 to March 4, 1921, during the last two years of...

, Sixty-seventh

67th United States Congress

The Sixty-seventh United States Congress was a meeting of the legislative branch of the United States federal government, consisting of the United States Senate and the United States House of Representatives. It met in Washington, D.C. from March 4, 1921 to March 4, 1923, during the first two years...

, and Sixty-eighth

68th United States Congress

The Sixty-eighth United States Congress was a meeting of the legislative branch of the United States federal government, consisting of the United States Senate and the United States House of Representatives. It met in Washington, D.C. from March 4, 1923 to March 4, 1925, during the last months of...

 Congresses and served from April 2, 1918, until his death in Chicago, Illinois, on May 4, 1923.
He was interred in Calvary Cemetery.