Belgian emigrants to the United States

Jean-Baptiste Frédéric Isidor, Baron Thielemans (29 April 1922 – 22 August 2016), known professionally as Toots Thielemans ([tuts tiləmans]), was a Belgian jazz musician. He was mostly known for playing the chromatic harmonica, as well as his guitar and whistling skills, and composing. According to jazz historian Ted Gioia, his most important contribution was in "championing the humble harmonica", which Thielemans made into a "legitimate voice in jazz". He eventually became the "preeminent" jazz harmonica player.His first professional performances were with Benny Goodman's band when they toured Europe in 1949 and 1950. He emigrated to the U.S. in 1951, becoming a citizen in 1957. From 1953 to 1959 he played with George Shearing, and then led his own groups on tours in the U.S. and Europe. In 1961 he recorded and performed live one of his own compositions, "Bluesette", which featured him playing guitar and whistling. In the 1970s and 1980s, he continued touring and recording, appearing with musicians such as Oscar Peterson, Ella Fitzgerald, Sarah Vaughan, Bill Evans, Dizzy Gillespie, Kenny Werner, Pat Metheny, Jaco Pastorius, Mina Mazzini, Elis Regina, Quincy Jones, George Shearing, Natalie Cole, Billy Joel, Paul Simon, and Paquito D'Rivera.
Thielemans recorded the soundtracks for The Pawnbroker (1964), Midnight Cowboy (1969), The Getaway (1972), Cinderella Liberty (1973), The Sugarland Express (1974) and Looking for Mr. Goodbar (1977). His harmonica theme song for the popular Sesame Street TV show was heard for 40 years. He often performed and recorded with Quincy Jones, who once called him "one of the greatest musicians of our time." In 2009 he was designated a Jazz Master by the National Endowment for the Arts, the highest honor for a jazz musician in the United States.

Jean-Charles Houzeau de Lehaie (October 7, 1820 – July 12, 1888) was a Belgian astronomer and journalist. A French speaker, he moved to New Orleans after getting in trouble for his politics in Belgium.
In the U.S. he continued his journalistic, astronomical, and political pursuits. He was an abolitionist and joined with unionists in Texas before the American Civil War. In New Orleans he worked with Dr. Louis Charles Roudanez at the newspapers he founded in the 1860s.
Houzeau migrated to Jamaica in the postwar years. After reinstatement from an observatory in Brussels, he returned to Europe to work. He came back to Texas for an astronomical event. He published stirring memoirs and other accounts of his adventures and contacts during his travels, as well as several works on astronomical subjects.

Charles Joseph Van Depoele (27 April 1846 – 18 March 1892) was a Belgian-American electrical engineer, inventor, and pioneer in electric railway technology, including the first trolley pole.

Theophile Meerschaert (24 August 1847 – 21 February 1924) was a Belgian-born prelate of the Catholic Church. He served as the Bishop of the Diocese of Oklahoma (and its predecessor) in the United States from 1891 until his death in 1924.

Zora Arkus-Duntov (December 25, 1909 – April 21, 1996) was a Belgian-born American engineer whose work on the Chevrolet Corvette earned him the nickname "Father of the Corvette.": 6  He is sometimes erroneously referred to as the inventor of the Corvette, whereas that title belongs to Harley Earl. He was also a professional racing driver, appearing at the 24 Hours of Le Mans four times and taking class wins in 1954 and 1955.

Georges Ugeux is a dual citizen of Belgium, his native country, and the United States, and was Group Executive Vice President of the New York Stock Exchange from 1996 to 2003. His banking career began in the 1970s in Europe, and he is currently the CEO of Galileo Global Advisors, a New York-based investment bank catering to emerging markets. He is a notable member of the Belgian diaspora, due to his influence in the world of international finance. He is a frequent public speaker and an op-ed contributor to the Huffington Post.

Karel Jan Bossart (February 9, 1904 – August 3, 1975) was an innovative rocket designer and creator of the Atlas ICBM. His achievements rank alongside those of Wernher von Braun and Sergei Korolev. But as most of his work was for the United States Air Force and was therefore classified, his achievements are not widely known.

George Alfred Leon Sarton (; 31 August 1884 – 22 March 1956) was a Belgian-American chemist and historian. He is considered the founder of the discipline of the history of science as an independent field of study. His most influential works were the Introduction to the History of Science, which consists of three volumes and 4,296 pages and the journal Isis. Sarton ultimately aimed to achieve an integrated philosophy of science that provided a connection between the sciences and the humanities, which he referred to as "the new humanism".