And, as he just revealed on Instagram, he couldn't be happier about that.
"@laurawbush and I are thrilled to welcome Henry Harold Hager to our family," the 43rd president wrote. "We are happy for the proud parents, @jennabhager and Henry. And pleased that Mila and Poppy have a little brother to love."
The 73-year-old Bush, who's known as "Jefe" to his grandchildren, shared two sweet family photos alongside that caption.
In the first pic, he and wife, Laura Bush, smile alongside their daughter's family of five — including Jenna herself, husband Henry Hager, their girls, Mila, 6, and Poppy, 3, and the "beautiful, funny little man" of the moment, Hal.
In another photo, Jefe beams alongside "Grammee," aka the former first lady, who has the new bundle of joy cuddled in her arms.
Grammee, 72, also shared her excitement about the family's newest addition in a post on her Instagram account.
"We are overjoyed by the birth of our darling grandson," Bush wrote. "Welcome to our family, Henry Harold 'Hal' Hager!"
The former first lady has been excited about having another grandchild since Jenna first announced her pregnancy.
In May, just one month after Jenna shared the happy news about having a baby boy on the way, Grammee visited TODAY and told us, "I'm thrilled about the new boy! Of course, George and I are just thrilled to have another grandchild. As George says, 'Grandchildren, they're the wonderful part about old age — the reward for old age.'"
TODAY viewers were in for another special treat on Monday when Jenna called in to TODAY. She explained that "Mila and Poppy came and picked him out in the nursery, and they're just crazy about him. ... The girls are so thrilled that they have a little baby brother all of their own."
And we're all thrilled to get to see Hal in these sweet new photos.
Former President Bush concluded his post by saying, "We thank God that mom and baby are healthy, and we look forward to many years of loving the boy known as Hal."
Hal is the first son for 37-year-old Jenna and the first grandson on both sides of his family.
Welcome to the family, Hal!