The name announcement came a week after Kim confirmed on Twitter that the baby boy had arrived after being born via a surrogate.
“He’s here and he’s perfect!” she tweeted.
Kim, 38, and Kanye, 41, have been married since 2014 and have three other children: North, 5; Saint, 3; and Chicago, 1.
Kim began using a surrogate after dealing with a number of issues during her first two pregnancies.
It’s not clear what inspired the name Psalm, a well-known book in the Bible. But Kanye has made his interest in religion known recently, even hosting a Sunday service at Coachella this year.
As for how much bigger Kim and Kanye want their family to get, in 2017, People magazine reported that the couple was open to having “five or six” children.