Almerine M. Alexander, merchant and Confederate officer, was born in Kentucky about 1821, the son of John Martin and Martha (Thurman) Alexander. He came to Texas with his brothers, C. C. and L. C. Alexander, in the 1840s. All of the brothers were merchants, and at various times they owned large stores in Paris, Clarkesville, Bonham, Dallas, and Sherman. A. M. Alexander first appears on county tax rolls in 1847 in Lamar County, where he and his brother L. C. were apparently partners in a store at Paris. In 1848 the Alexanders moved to Dallas and opened a store, A. M. Alexander and Brothers. It became the largest retail firm in Dallas before closing in 1853. In the spring of 1849 Alexander married Josephine B. King of Burkesville, Kentucky, in Nashville, Tennessee. The couple had three children. In late 1850 Alexander left the Dallas store to be run by a manager and moved to Sherman, where he opened a firm in his own name. He closed that store a year later and moved to Bonham, where he and his brothers had a store. In late 1854 he moved back to Sherman and opened a store in partnership with S. B. Allen. Alexander continued to live in Sherman until he left for service in the Confederate Army; the firm of Alexander and Allen remained in operation until Alexander's death.
In the winter of 1861–62 Alexander raised the Thirty-fourth Texas Cavalry regiment, also known as the Second Texas Partisan Rangers, in Sherman. This regiment was one of three Texas cavalry regiments brigaded for the first time in July 1862. They were charged with defending the Trans-Mississippi Department and for the next three years were marginally successful in doing so. After engaging federal troops at Spring River and Newtonia, Missouri, in the fall of 1862, the Thirty-fourth, weakened by sickness, poor morale, and frequent desertions, was dismounted and reduced to an infantry unit. On December 7, 1862, the newly designated Thirty-fourth Texas Dismounted Cavalry engaged Union forces at Prairie Grove, Arkansas. Although the regiment was successful in fending off a series of charges, dwindling ammunition forced them to retreat.
Following Prairie Creek, the Thirty-fourth was merged with the Fifteenth Texas Infantry. In February 1863 Alexander was made acting commander of Lt. Col. Joseph Warren Speight's brigade, a position he held until May of that year, when poor health forced him to resign. Fellow officers considered Alexander “utterly unfit” for the colonelcy, perhaps due to “intemperance.” He spent the remainder of the war based in San Antonio, buying and shipping cotton to Mexico under permit from the Texas Cotton Board. Much of the cotton was confiscated by the federal government when the war ended, and the family filed several lawsuits to recover the proceeds, He died in New Orleans July 23, 1865, while on a business trip connected with the suits, and was buried there in Girod Street Cemetery.