The two global leaders, vastly different in temperament and views of the world, talked seriously and extensively in a 30-minute private meeting about terrorism, the radicalization of young people, immigration and climate change, officials said.
Grisham, the first lady's communications director, would not comment as to whether the first couple would raise their son in the Catholic faith, nor did she answer a request for specifics about Melania Trump's religious habits, including whether she regularly attends Mass.
Prompted by European Council President Donald Tusk, who called images of the Saudi visit "spectacular", Trump replied: "It was very spectacular".
The Holy See said in a statement that the meeting was "cordial". As is tradition, the pope and president then exchanged gifts.
Still, experts believe it unlikely the outspoken pope will do anything but be welcoming during his first meeting with Trump.
Trump, accompanied by first lady Melania Trump, son-in-law and adviser Jared Kushner, daughter Ivanka Trump and Secretary of State Rex Tillerson, presented the pope a first-edition collection of Martin Luther King's writings.
Others made a decision to Photoshop the image after all.
"It is my desire that you become an olive tree to construct peace", the Pope said in Spanish.
Meanwhile, Trump called the meeting "great" and "fantastic" and tweeted that it was an honour to meet His Holiness, despite the fact he previously called the Pope's comments about a wall between the USA and Mexico being "not Christian" as "disgraceful". The pope also gave Trump a medallion depicting an olive branch as a symbol of peace. At one point, the Pope jokingly asked Melania, "what she fed her husband", the Guardian reported.
Like Melania Trump, former first ladies Laura Bush and Hillary Clinton have forgone headscarves when visiting the country. And in Israel, Trump reaffirmed his commitment to strong ties with the nation's longtime ally and urged both the Israelis and the Palestinians to begin the process of reaching a peace deal.
Later on Wednesday, Mr Trump will fly to Brussels, where significant protests are expected.