Niels Juul 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 Randers, Denmark, Juul attended the Real School, Randers, Denmark.
He emigrated to the United States and settled in Chicago

Chicago

Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...

, Illinois, in 1880. He engaged in the publishing business. He studied law, and graduated from the law department of Lake Forest University in 1898. 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 1899 and commenced practice in Chicago.

He served as member of the State senate from 1898 to 1914. He served as assistant attorney of the Sanitary District of Chicago from 1907 to 1911.

Juul was elected as a Republican

Republican Party (United States)

The Republican Party is one of the two major contemporary political parties in the United States, along with the Democratic Party. Founded by anti-slavery expansion activists in 1854, it is often called the GOP . The party's platform generally reflects American conservatism in the U.S...

 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...

 and 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...

 Congresses (March 4, 1917 - March 3, 1921). He was an unsuccessful candidate for renomination in 1920.

He was appointed by President Warren G. Harding

Warren G. Harding

Warren Gamaliel Harding was the 29th President of the United States . A Republican from Ohio, Harding was an influential self-made newspaper publisher. He served in the Ohio Senate , as the 28th Lieutenant Governor of Ohio and as a U.S. Senator...

 United States Collector of Customs for the Port of Chicago

Port of Chicago

The Port of Chicago consists of several major port facilities within the city of Chicago, Illinois operated by the Illinois International Port District . The central element of the Port District, Calumet Harbor, is maintained by the U.S...

 on January 1, 1921, and served until December 31, 1922, when he resigned.

He resumed the practice of law until his death in Chicago, on December 4, 1929.
He was interred in Mount Olive Cemetery.