Sam Acheson, journalist and historian, was born to Alexander Mahon and Alice (Hanna) Acheson on August 21, 1900, in Dallas, Texas. He attended Dallas public schools, Austin College, and then, from 1917 to 1921, the University of Texas, where he received a bachelor's degree in English in 1921. In 1918 he was selected as an officer candidate by the United States Marine Corps, but he was still in training at Camp Mabry when World War I ended.
For two years in the early 1920s Acheson worked as a reporter for the Dallas Times Herald, then moved to the Dallas Morning News in 1925. There he worked as a reporter, an editor, and an editorial writer until his retirement in 1966. During World War II he was appointed to the Enemy Alien Hearing Board for the Northern District of Texas but quit to join the army as a captain. He served in Europe, received the Bronze Star, and attained the rank of major. He later retired from the reserves as a lieutenant colonel.
Acheson's works include Joe Bailey: The Last Democrat (1932), nominated for the Pulitzer Prize; 35,000 Days in Texas (1938), a history of the Dallas Morning News and its parent news agencies hailed as "one of the first socioeconomic histories of the state"; and a historical play dramatizing the fall of the Alamo, We Are Besieged (1941). Acheson was a contributor to American Mercury, the Dictionary of American Biography, and the Dictionary of American History. He was a compiler of Texian Who's Who (1937) and an editor of George Washington Diamond's Account of the Great Hanging at Gainesville, 1862, published in 1963 by the Texas State Historical Association, of which he was a fellow. Acheson was considered the leading authority on Dallas during his lifetime; after he retired he continued to write a weekly series, "Dallas Yesterday," for the News. This column was assembled into a book and published posthumously in 1977.
Acheson served as secretary of the Dallas Historical Society from 1935 until his death and was instrumental in persuading the city of Dallas to lease the Hall of State from the state and invite the historical society to maintain the library and museum there. He was secretary of the Philosophical Society of Texas from 1940 to 1972, a director of the Dallas Civic Federation and Community Chest Foundation, and a member of the American Legion, the Military Order of the World Wars, the Texas Institute of Letters, the University Club, and the Beta Theta Pi fraternity. At the time of his death he was serving as consultant to the executive vice president of the Southwestern Legal Foundation.
Acheson was a Presbyterian and a Democrat; he never married. On March 7, 1972, he died at his home in Dallas. He was buried in Denison.