as a private two days after President Abraham Lincoln called for volunteers. Krzyżanowski recruited a company of Polish immigrants, one of the first companies of Union soldiers. He moved the company to New York City, enlisted more immigrants, and soon became colonel of the 58th New York Volunteer Infantry Regiment, listed in the official Army Register as the "Polish Legion". Krzyżanowski participated in the battles of Cross Keys in the Shenandoah Valley, and Second Bull Run (Second Manassas), where he was injured when his horse fell, Chancellorsville, where his brigade and the corps they were part of were routed by a Confederate flank attack, and Gettysburg in the Eastern Theater. President Lincoln appointed Krzyżanowski brigadier general on November 26, 1862. The appointment expired by law on March 4, 1863, because the U.S. Senate failed to confirm the promotion. The Senate belatedly approved the appointment on March 9, 1863, but recalled it March 11, 1863, returned it to President Lincoln on March 12, 1863, and tabled it on March 13, 1863, keeping the expiration of the appointment in effect. At Gettysburg on 1 July 1863 his men were pushed back through the town as the Union XI Corps retreated. During this action, Krzyżanowski was injured when his horse stumbled. However, next day he led a counterattack on Cemetery Hill that helped stabilize the faltering Union line. Later in the year, the XI Corps was sent to the Western Theater to help raise the Confederate siege of Chattanooga. Krzyżanowski played a role in the Battle of Wauhatchie, where he followed Maj. Gen. Joseph Hooker's orders very literally, and was present at the Battle of Missionary Ridge. When the XI Corps was dissolved, much of it being added to XX Corps, Krzyżanowski was assigned to command at Bridgeport, Alabama, to guard the Nashville and Chattanooga Railroad, and later to Stevenson, Alabama, both commands within the Department of the Cumberland. He also commanded the 3rd Brigade of the Defenses of the Nashville & Chattanooga Railroad, reporting to Maj. Gen. Robert H. Milroy. On 2 March 1865 President Lincoln nominated Krzyżanowski for appointment to the grade of brevet brigadier general of volunteers, to rank from 2 March 1865. The U.S. Senate confirmed the appointment on 9 March 1865. Krzyżanowski was mustered out of the volunteers on 1 October 1865. Postbellum After the war, Krzyżanowski was given governing duties in Alabama. He later served as the