A German revolutionary and lawyer, Friedrich Karl Hecker was a leader of the opposition in the grand duchy of Baden during the revolutionary agitation of 1847–49 in Germany.  He was an organizer of demands for democratic parliamentary government, and in 1848 led an unsuccessful uprising in Baden that proclaimed a constitutional republic. Hecker was subsequently forced into exile and settled permanently in the United States. 

Friedrich Karl Hecker was born in Eichtersheim, Grand Duchy of Baden, on 28 September 1811.  He was the son of a well-to-do councilor of Prince von Dalberg.  He was educated at the Gymnasium in Mannheim, and then studied law at the universities of Heidelberg and Munich before receiving a doctorate in law degree at Heidelberg. After an additional year of  legal studies in Paris in 1835/6, he began practicing law in Mannheim in 1838. In 1839, he married Marie Josephine Eisenhardt, member of a prominent Mannheim family.

Hecker entered politics in 1842 when he won a seat in the lower chamber of the Baden State Assembly. He was a prominent member of the "Liberal" wing of the Assembly, where he became famous for his dramatic speeches and actions aimed at gaining popular support. In 1845, he achieved notoriety all over Germany for opposing the incorporation of the German-speaking provinces of Schleswig and Holstein into Denmark.  Hecker became one of the most important leaders of the German Left because of his open criticism of the government of Baden and other German principalities before the outbreak of revolution in March 1848.  In March 1848 he called for an assembly of the people and the elimination of princely governments.  When he realized that the call for an assembly was not succeeding, Hecker joined others in calling on 12 April 1848 for a general armed uprising on behalf of a German Republic. A small force of revolutionaries marching through the Black Forest was defeated on 20 April 1848 by troops commanded by General Friedrich von Gagern (who died in the battle).  Hecker fled to Switzerland, and then departed for America after attempts to continue the revolt from exile failed.

Hecker bought a farm near Belleville in southern Illinois.  He was considered a hero by many German-Americans, since he had never compromised with the princely governments or accepted amnesty for his revolutionary actions.  He used his savings to buy land in St. Clair County, Illinois, and began raising grapes using the latest scientific techniques. Although he earned a steady income from making speeches in both German and English, he never held a political office in the United States.  He was an early member of the Republican Party, though he was in the Fremont wing rather than the wing led by Lincoln and later by General Grant. In the 1870s, he would support the Liberal Republican wing under Carl Schurz. He was personally opposed to slavery, though he never was a strong supporter of black rights.

In the spring of 1861, Hecker signed up as a private in a regiment of Missouri volunteers organized by fellow Baden revolutionary Franz Sigel.  Hecker was soon called back to Illinois to command a newly-organized regiment of German volunteers from the Belleville area, the 24th Illinois Volunteer Infantry. This regiment experienced difficulties almost as soon as it went into action, due to skepticism about Hecker's military abilities on the part of some of his junior officers.  By the end of 1861, the regiment was sent back to Springfield, Illinois, and disbanded.  After several months at home, Hecker was asked to head a German regiment recruited from the Chicago area, the 82nd Illinois Volunteer Infantry Regiment. This unit saw hard service in Virginia and Tennessee, and Hecker himself was wounded at the Battle of Chancellorsville (May 1863). He returned to service and led the regiment until he resigned in protest against perceived mistreatment by his commanding officers during the battle for Lookout Mountain, Tennessee, on 24 November 1863.

After the Civil War, Colonel Hecker continued to be active as a speaker on Republican issues, and wrote articles for the German press.  In 1870 he supported the establishment of a unified Germany under Prussian leadership, since he believed that liberalization of the authoritarian regimes would soon follow. In 1873 he made a speaking tour of Germany, where he was very well known. On his return to Illinois, he continued to involve himself actively in politics, though he also traveled to Colorado to gain relief for respiratory troubles. He died on 24 March 1881 on his farm in Summerfield, Illinois, and is buried in the Summerfield cemetery under a US Army tombstone as Col. Frederic Hecker, 82nd Illinois Infantry.