Beevers married Marjorie Pollard in 1934. He published his first book, World Without Faith, a defense of free thought over structured ideology, the following year. Beevers also began his journalism career at this time with stints on several newspapers. He worked exclusively for the British Broadcasting Corporation from 1941 to 1969.

John Beevers embraced revolutionary Communism in the 1930s, but converted to Roman Catholicism sometime in the 1940s. Although nominally a Catholic, Beevers had an ambiguous relationship to the church. While he admired its theology and the lives of Catholic saints, Beevers’s critical and lascivious nature prevented him from fully committing to the faith, particularly in its moral elements. Marjorie Beevers demonstrated a greater devotion to Roman Catholicism than her husband.

John Beevers aspired to write fiction and poetry, but never had much success in these genres. He privately printed a volume of poetry, The Dark Emperor, under the pseudonym John Clayton in 1947, but failed to publish any more imaginative literature. Instead, Beevers turned to writing biographies of Roman Catholic saints, beginning with Storm of Glory: St. Therese of Lisieux (1949). John Beevers is best known for his 15 works on saints’ lives, Marian apparitions, and translations of Catholic theological treatises. He has been credited with presenting balanced accounts of his subjects, avoiding both brusque skepticism and unquestioning piety.

John and Marjorie Beevers had one daughter, Susan Jane. Marjorie Beevers died in 1962. John Beevers married his mistress, Marjorie Broadbridge, the following year. He continued writing until his death on 13 September 1975.