Here's the list sorted by year:
- John Beckley, 1872 & 1884-1896 (Founder of Beckley)[2]
- Thaddeus K. Scott, 1891
- Robert T. Willis, 1893
- Thaddeus K. Scott, 1894
- Capt. John W. Anderson, 1897
- John Wallace McCreery, 1898–1899
- J. E. Summerfield, 1900
- John Wallace McCreery, 1901
- George A. Cook, 1901
- A. D. Preston, 1902
- John H. Hatcher, 1903
- Ashton File, 1904
- Joe L. Smith, 1906[3]
- Hugh A. Dunn, 1907
- Joe L. Smith, 1908-1909[3]
- Lucien Hereford Davis, 1910–1911
- Thomas H. Wickham, 1911
- M. L. Painter, 1912–1913
- Dr. W. W. Watts, 1914–1915
- Hugh A. Davis, 1916–1917
- Herbert A. Stansbury, 1918–1919
- Dr. J. A. Campbell, 1920–1921
- C. V. Cottle, 1922–1923
- Herbert A. Stansbury, 1924–1925
- J. Hugh Miller, 1926–1927
- Joe L. Smith, 1928-1929[3]
- George W. Bair Jr., 1929
- Cyrus H. Meador, 1930–1931
- Grover C. Hedrick, 1932–1933
- A. Z. Lilly, 1934–1935
- Robert Wriston, 1936–1937
- A. K. Minter, 1938–1939
- A. K. Minter, 1940–1941
- A. K. Minter, 1942–1943
- Robert Wriston, 1944–1945
- Walter A. E. Burke, 1946–1947
- Grover C. Hedrick, 1948–1949
- Walter A. E. Burke, 1950–1951
- George Chambers, 1952–1953
- Elmer L. Davis, 1954–1955
- A. K. Minter, 1956–1959
- Cecil Miller, 1959–1963
- John Wesley Smith, 1963–1970
- John Howard McCulloch, 1970–1982
- Charles F. Shoemaker, 1983–1987
- Emmett S. Pugh III, 1988–2013
- William A. O’Brien, 2014–2016
- Robert Rappold, 2016–Present[4][5]
Berkeley, Edmund; Berkeley, Dorothy Smith (1975). "The First Librarian of Congress: John Beckley". The Quarterly Journal of the Library of Congress. 32 (2): 83–117. JSTOR 29781617.