Steinberg eventually moved away from art criticism and developed a scholarly interest in such artists and architects as Francesco Borromini, Michelangelo, and Leonardo da Vinci.
[3] In 1960, he earned his PhD at New York University's Institute of Fine Arts with a dissertation on the architectural symbolism of Borromini's San Carlo alle Quattro Fontane in Rome.
From 1995 to 1996, Steinberg was a guest professor at Harvard University, delivering the Charles Eliot Norton lectures on "The Mute Image and the Meddling Text."
Steinberg approached the history of art in a revolutionary manner, helping to move it from a dry consideration of factual details, documents, and iconographic symbols to a more dynamic understanding of meaning conveyed via various artistic choices.
In that essay, Steinberg examined a previously ignored pattern in Renaissance art, which he named ostentatio genitalium: the prominent display of the genitals of the infant Christ and the attention also drawn to that area in images of Christ near the end of his life, in both cases for specific theological reasons involving the concept of the Incarnation – the word of God made flesh.
[11][12] Steinberg's research particularly focused on the works of Michelangelo, Leonardo da Vinci, and other Italian Renaissance artists and their depictions of Christ in art.