In 1830, Alexander Doniphan migrated from Kentucky to Lafayette County, Missouri. He did so to open a law practice. He held his highest interest in a career as a lawyer, but won his greatest fame as a military leader. Doniphan first gained his reputation for military leadership during Missouri's 1838 Mormon War. As commander of the First Brigade of the Missouri militia, Doniphan was sent to apprehend Joseph Smith and other Mormon leaders. After capturing Smith, Doniphan received an order calling for Smith's immediate execution. He refused the order, telling his commanding officer, "I will not obey your order. It is cold-blooded murder." Doniphan's bravery not only saved Smith's life but also ended the Mormon War with a minimum of bloodshed.
Doniphan again led Missouri troops in 1846, this time during the Mexican War. His volunteers, rough-hewn Missouri frontiersmen, were unaccustomed to military discipline, but Doniphan won their loyalty and turned them into an effective fighting force. In 1847 he led his outnumbered troops into battle against better-equipped Mexican forces at the Battle of Brazito and Sacramento. Doniphan's strategic skill and the fighting spirit of Missouri's volunteers led to decisive American victories in both engagements. Doniphan also played a key role in restoring law and order to the Mexican region. As military governor of Santa Fe, he revised the region's civil and criminal codes and established a bill of rights for New Mexico citizens.
Colonel Doniphan spent the remainder of his life as a lawyer and a statesman. He served several terms in the Missouri General Assembly, and he was selected as Missouri's representative to the 1861 national peace conference, where delegates worked for a solution to avert civil war. At the 1861 state convention held to decide whether Missouri would secede, Doniphan arrived with his allegiance to keep Missouri in the Union. When the Civil War broke out, Governor Claiborne Jackson offered him command of Missouri's State Guard (Confederate), but Doniphan refused the commission, citing the recent death of his sons and his wife's ill heath. From 1863 to 1868, He lived in St. Louis and served as the U.S. Commissioner of Claims for Missouri.
In 1868, Doniphan returned to western Missouri, moving to Richmond in Ray County. He spent his remaining years arguing cases throughout northern Missouri.
[Historic information coming from an essay by James W. Goodrich.]