In mid-1857 Johnston commanded an expedition against insurgent Mormons in Utah. His campaign began that fall but was delayed until the following spring by severe weather. Following a series of negotiations, Johnston's army marched unopposed into Salt Lake City in June 1858. Promoted to brevet brigadier general that year, he remained in Utah until February 1860. Following his reassignment as commander of the department of California, Johnston reluctantly decided to resign from the U.S. Army in April 1861 when he learned that Texas had seceded. After a difficult three-month overland journey from Los Angeles to Richmond, Virginia, Johnston was appointed a full Confederate general, with rank second only to Adjutant General Samuel Cooper, and placed in command of the vast territory stretching from the Appalachian Mountains to Indian territory.
Wiley Sword, "Johnston, Albert Sidney," American National Biography Online, February 2000,http://www.anb.org/articles/04/04-00574.html.