"Carter York Nickson. Born 05OCT2020 at 2223. 7lbs 2oz 19.5 inches," Jessica and Cody captioned a photo of the swaddled baby on the newborn's Instagram account, which had been used to document Jessica's pregnancy progress and growing baby bump.
Cody also revealed in his Instagram Stories, "Healthy and safe delivery for mom and baby... Thank you for all the prayers!"
In addition, Cody secretly posted the address to the medical center where Jessica gave birth so fans could send her flowers and/or balloons.
Jessica and Cody's baby was due October 15 so she arrived a little early, according to E! News, shortly before the couple's second wedding anniversary.
Carter York joins her older sister Maverick, 1, and Cody's eight-year-old daughter Paisley from a previous relationship.
Earlier on Monday, Jessica teased her baby was on the way.
"WE'RE HAVING A BABY TODAY!!" Jessica captioned a sweet family photo on Instagram.
"My blood pressure just doesn't want to stay down so my doctor says it's baby day. Just checked into the hospital and we expect @babynickson to be out in the world in a few hours."
Cody subsequently posted videos to Jessica's Instagram Stories of the couple in the hospital trying to pass the time before Jessica's "scheduled C-section." Jessica was dancing in her hospital gown and admitted she was pretty hungry but not allowed to eat before the procedure.
"FINALLY! As you guys know, Cody and I have been wanting to have all our kids pretty close in age so we were determined to get pregnant this year," Jessica wrote at the time.
"A part of me wanted to straight Kylie Jenner it and tell you guys after the birth but after several accidental IG stories with our ultrasound peaking through in the background, we knew it was time to come clean."
"Maverick is going to be a big sister! I'm not really sure if she fully understands that yet but no matter what, she's always going to be my baby."
The couple then unveiled the sex of their second child one week later by posting a gender-reveal video to Jessica and Cody's YouTube channel on May 12.
In the video, Jessica stood closely next to Cody in the backyard of their home as he shot off a confetti cannon and pink paint and confetti filled the air, revealing the couple had another baby girl on the way.
"It's a girl!!!" flashed across the screen as Jessica and Cody hugged each other and celebrated.
Big Brother alum Elena Davies filmed the gender reveal for Jessica and Cody, who fell in love on Season 19 of Big Brother in 2017 and then got engaged on February 13, 2018 shortly after winning the $1 million prize on The Amazing Race's 30th season.
"Cody is good at making girls!" Elena joked from behind the camera.
Jessica did not debut her first baby bump until December 2018 when she was 22 weeks along with Maverick in order to avoid haters and trolls, but Jessica was much more confident and open with fans during her second pregnancy.