According to Diane McWhorter’s Carry Me Home: The Climactic Battle of the Civil Rights Revolution, [New York Times Magazine Editor Walter] Shapiro phoned the offices of King’s organization, the Southern Christian Leadership Conference, in July 1962. King was doing jail time in Albany, Georgia, on charges of disturbing the peace while protesting the segregation of public facilities. Shapiro suggested that King write a “letter from prison” modeled on those of early Christian saints; Shapiro may also have been thinking about another 20th century political martyr and Christian minister, Dietrich Bonhoeffer…
…The following May, King was once again in jail for staging a nonviolent protest, this time in Birmingham, Alabama. King remembered Shapiro’s offer… King scribbled a response in the margins of the newspaper, on toilet paper, and and on other scraps that his lawyers sneaked out to the SCLC’s executive director, Wyatt Walker, who got it transcribed. Walker passed drafts back and forth through the lawyers until King was satisfied.
Up north at the Times Magazine, Shapiro was eager to publish, but (according to McWhorter) he “could not get the letter past his bosses at the Times.” Way to go, Gray Lady!
The Times, S. Jonathan Bass reports in Blessed Are The Peacemakers: Martin Luther King, Eight White Religious Leaders, and the ‘Letter From Birmingham Jail,’ initially scheduled the letter for publication in late May. But first it wanted (in the recollection of King adviser Stanley Levison) a “little introduction setting forth the circumstances of the piece.” Then it decided, no, what it really wanted was for King to “write a feature article based on the letter.” Or, possibly, it wanted both. Before King had a chance to jump through these hoops, the New York Post (in those distant days a plausible rival to the Times) got a copy of the letter and published unauthorized excerpts, killing the Times’s interest.