Civil War Union Brevet Brigadier General. He began his service in defense of the Union soon after the Confederate bombardment of Fort Sumter, South Carolina, being commissioned as Captain and commander of Company K, 6th Pennsylvania Volunteer Infantry on April 22, 1861. The unit served first in Maryland, then in Virginia, and saw no action other then skirmishing. Mustered out then the regiment's enlistment expired on July 27, 1861, he helped raise and organize the 48th Pennsylvania Volunteer Infantry, which was made up mostly of miners from the coal fields of Schuylkill County, Pennsylvania. Commissioned Major of the regiment on October 1, 1861, a month later he was advanced to Lieutenant Colonel to fill the vacancy in that position. Over the nest year he was with his men as they fought in March 1862 at New Bern, North Carolina, at Groveton, Manassas and Chantilly during the August 1862 2nd Bull Run Campaign, and in the September 1862 Antietam Campaign. When the 48th's commander, Colonel James Nagle, was promoted to Brigadier General on September 10, 1862, Joshua K. Sigfried was advanced to Colonel and commander ten days later. He led his regiment during the December 1862 Battle of Fredericksburg, and through the Winter of 1862-1863. In March 1863 the regiment was sent west to Lexington, Kentucky, where he performed the duty of Provost Marshall until September 10, 1863. Advanced to Brigade command when his Corps was detailed later that month south to the Army of the Ohio operating in Tennessee, he led his brigade in the November-December 1863 Battle and Siege of Knoxville. In April 1864 given command of a brigade of United States Colored Troops in the division of Brigadier General Edward Ferrero. The Corps, having returned to the Virginia Theatre of operations, fought during the Siege of Petersburg, and at the July 1864 Battle of the Crater, Colonel Sigfried's men were sent in unsupported and sustained heavy casualties. On October 11, 1864 his original enlistment expired by law, and he was honorably mustered out of Federal service, having been brevetted Brigadier General, US Volunteers on August 1, 1864 for "great efficiency in organizing and disciplining a brigade of colored troops". After the war he became involved with mining and railroad interests in Schuylkill County, and rose to the rank of Major General in the Pennsylvania National Guard.