Franz Sigel was born in 1824 in Sinsheim, Baden (a German duchy).  After graduating from the German Military Academy at Karlsruhe in 1843, he served as a lieutenant in the Baden army.  In 1848-1849, he played a key role in an unsuccessful liberal revolution.  Forced to flee to Switzerland in 1848 when the uprising was initially put down, he returned the next year as secretary of war when a rebel government briefly held power.  After leading the rebel Baden army against the Prussians, he was compelled to retreat again to Switzerland, where he was held in high regard by his fellow exiles. 

In 1851, Sigel moved to England, and the following year to New York City, where he labored at various occupations and taught at a private academy for German immigrant children.  He also joined the New York state militia, and wrote for The New York Times and the German-language New Yorker-Staats-Zeitung.  He moved to St. Louis in 1857, where he taught at the German-American Institute, and became director of the city’s schools. 

When the Civil War began in April 1861, Sigel encouraged German-American men to volunteer, and he enlisted as a colonel with the Third Missouri Infantry.  He helped capture Camp Jackson on May 10, and was raised to the rank of brigadier general on August 7.  Although military historians today criticize his leadership at the Union defeat of Wilson Creek on August 10, he continued to receive favorable notice in Republican and German-American newspapers at the time.  The friendly press also exaggerated his contributions as commander of two divisions at the Battle of Pea Ridge, Arkansas (March 6-8, 1862).  On March 21, 1862, Sigel was promoted to the rank of major general.  When he was soon after transferred to Virginia, enthusiastic supporters greeted his train along the way. 

Sigel first received bad press when he spread rumors and testified without evidence before a military inquiry that General Irvin McDowell had sabotaged General John Pope’s military plans at the Second Battle of Bull Run (August 29-30, 1862).  In February 1863, Sigel was demoted, and he resigned his new post in protest.  Thereafter, he trained militia troops in a Pennsylvania district until, after heavy lobbying, he was given command of the Department of West Virginia on February 29, 1864.  He was defeated and forced to retreat at New Market, Virginia, on May 15, and relieved of his command four days later.  His delays led to defeat at Harper’s Ferry, West Virginia, in July 1864, and he was relieved of duty for his “lack of aggression.”  He formally resigned from the Union Army on May 4, 1865.