Henry Alan Johnston (1885-1956) was a New York City lawyer, banker, and author, who was a founder, director, and officer of the Thomas Jefferson Memorial Foundation (later renamed the Thomas Jefferson Foundation) from 1923 until his death in 1956.

Born in 1885 in Washington, D.C., Johnston received an undergraduate degree from Davidson College in 1903, a Master's degree from Princeton University in 1904, and a law degree from the University of Virginia in 1909. In that year, he was admitted to the Virginia Bar and practiced law in Norfolk for several years before moving to New York City where he practiced law with Stuart G. Gibboney in the firm of Gibboney, Johnston, and Flynn. He was later a member of the law firm of Clark, Carr, and Ellis. He served as a director of the Industrial Bank of Commerce of New York, of the Bankers Security Life Insurance Society, of the Barter Theater of Virginia, Inc., and was a legal adviser to the United Kingdom-United States Steel Control Group of Dusseldorf, Germany. During World War I he was a lieutenant in the Navy and served as Chairman of the United States Navy Board for Commandeering from 1917 to 1919.

Johnston's interest in Thomas Jefferson extended beyond the Thomas Jefferson Memorial Foundation. In 1927 he served as the Secretary of the National Jefferson Centennial Commission and he later assisted in obtaining an appropriation from Congress to establish the Jefferson Memorial in Washington, D.C.

In 1923, Johnston was named as one of the incorporators of the Thomas Jefferson Memorial Foundation. At the Foundation's first organizational meeting held at the Lawyers Club in New York on April 24, 1923, he was elected Secretary and was also elected to the important Executive Committee which drew up the Foundation's Constitution and By-laws, and also negotiated with Jefferson Monroe Levy to reach a firm arrangement for the purchase of Monticello. He served as Secretary from 1923 until May of 1944, when, following the death of Stuart G. Gibboney, he was elected Vice-President. He was elected to the Board of Directors in 1923 and served on the Board for 33 years until his death in 1956.

Johnston died in London while on a European tour on August 24, 1956.

- Anna G. Koester, 1998. Originally published in Anna G. Koester, Thomas Jefferson Memorial Foundation Archives: Collection Guide and Catalog, October 1998, pp. 9-10.