He was a specialist on the hypothetical Johannine community, which he speculated contributed to the authorship of the Gospel of John, and he also wrote studies on the birth and death of Jesus.

While it stated that Scripture teaches "solidly, faithfully and without error that truth which God wanted put into sacred writings for the sake of salvation,"[7] Brown pointed out the ambiguity of this statement, which opened the way for a new interpretation of inerrancy by shifting from a literal interpretation of the text towards a focus on "the extent to which it conforms to the salvific purpose of God."

"[9] Thirty years later, Brown revisited the issue in an introductory text for the general public, writing, "three reasonably clear instances in the NT (Hebrews 1:8–9, John 1:1, 20:28) and in five instances that have probability, Jesus is called God," a usage Brown regarded as a natural development of early references to Jesus as "Lord".

"[12] Terrence T. Prendergast stated that “for nearly 40 years Father Brown caught the entire church up into the excitement and new possibilities of scriptural scholarship.

[17][18] Brown's scholarship was controversial for questioning the inerrancy of the whole of scripture and casting doubt on the historical accuracy of numerous articles of the Catholic faith.

[19] He was regarded as occupying the center ground in the field of biblical studies,[20] opposing literalism found among many fundamentalist Christians but not carrying his conclusions as far as many other scholars.

Gilsdorf defined Brown's work as "a major contribution to the befogged wasteland of an 'American Church' progressively alienated from its divinely constituted center.

Literary critic Frank Kermode, in his review of The Birth of the Messiah, accused Brown of being too eager to secure the imprimatur of the Catholic Church.

[21] The Hebraic Jesus scholar Géza Vermes, speaking of the Nativity narratives, has described Brown's coverage as "the primary example of the position of having your cake and eating it.

"[22] In his obituary for The New York Times, Gustav Niebuhr wrote: "Father Brown was regarded as a centrist, with a reputation as a man of the church and a rigorous, exacting scholar whose work had to be reckoned with.