[citation needed] His achievements in letters were threefold: his discovery of the Puritan poet Edward Taylor (c. 1664–1729), whose Poetical Works[1] he issued in 1939; his co-editorship of Literary History of the United States[2] (1948, 3 vols.)

His father served as a captain during the Spanish–American War and later, when appointed Adjutant General of the State of Vermont, moved his young family to Montpelier.

Johnson wrote President Ernest Martin Hopkins for a third chance and received the reply, “Your letter is a mighty good one and even if it had not been found so unwise to deviate from our policy I should accept your ability to write a letter of this kind as indicating that you could make good in your college course.” But Johnson, who had written President Hopkins, “My greatest, my earliest ambition has been swept away from me because of my own carelessness.

[citation needed] By the time Tom graduated from Williams in 1926, he had been elected to the “Gargoyle” honor society and served as president of the college's theatrical group, “Cap and Bells".

The project, combined formal education with travel and integrated elite colleges and state schools from across the country, and it was covered nearly weekly by the New York Times.

In 1935 his interest in Colonial Literature can be seen in his Jonathan Edwards: Representative Selections,[10] edited with Clarence Faust of the University of Chicago, followed by The Puritans,[11] authored with Perry Miller of Harvard, in 1938.

By this time Johnson had married Catherine Rice, a Mount Holyoke graduate whom he had met while at Williams, and had begun teaching at the Hackley School in Tarrytown, New York.

[citation needed] Next came the Literary History of the United States,[2] published in three volumes by Macmillan in 1948, a collaboration with Robert E. Spiller of the University of Pennsylvania, Willard Thorp of Princeton and Henry Seidel Canby, founding editor of the Saturday Review of Literature.

Though as Vanderbilt wrote, “Thomas Johnson was not the foremost bibliographer on the American literature scene when Spiller and Thorp drove down from Princeton to nearby Lawrenceville School in 1942 and persuaded him to join the editorial board in that capacity.

For the academic year of 1951–1952, Johnson took his young family to Denmark where, supported by a Guggenheim grant, he set up such courses at the University of Copenhagen.

"[13] In 1966, came his last major work, The Oxford Companion to American History,[6] a one-volume reference that Alexander R. Butler, in his review in The New Republic, wrote, "the book invites browsing" and continued, "Johnson has set an exceptionally high standard for his possible successors.

"[14] Kermit Vanderbilt pointed out, "he clearly thrived on the alternation between prep-school instruction and the intense concentration demanded of textual and bibliographical scholarship.