Born on Feb. 27, 2015, Isaiah is the first child Underwood and Fisher share. When Isaiah was 3 years old, Underwood announced that he'd be a big brother before turning 4 in February 2019, and his baby brother came just under a month before!
On his fifth birthday, Underwood shared a photo of Isaiah as a newborn and penned a lovely tribute to her boy. "He is five today. Where did these last five years go?" she wrote. "It's so bittersweet watching your children grow up. You want them to stay little and chubby and cuddly forever but it's also so much fun seeing them turn into little people! Isaiah, you are funny and smart and such a caring little boy! You already have so much love for God and for all those around you. The day I became your mother was the day my life changed forever. You are five today but you will always be my baby boy...no matter how old you get. Thank you for being you."
In the fall of 2020, Isaiah made his singing debut on Underwood's first-ever Christmas album, "My Gift," with the song "Little Drummer Boy." He shared his voice with the world again in honor of "My Gift: A Christmas Special From Carrie Underwood" on Max. "So happy we captured the sweetest voice in this special moment in time," Underwood captioned an Instagram photo of herself and Isaiah in the recording booth. "My own Little Drummer Boy will be a part of the #MyGift Christmas Special."
Then, on Isaiah's seventh birthday, Underwood posted a sweet tribute to him on Instagram. "My firstborn turned 7 today. How is that even possible?" she wrote. "It has been so much fun to see this little dude grow! He has the biggest heart and the brightest smile. His love for Jesus is strong and pure. He is an old soul with a vintage style . .. wise beyond his years. He's the kind of kid that would rather raise money for the kids at @danitaschildren than get gifts for himself! What 7 year old does that?!?! I am so blessed to be his mom and I can't wait to see where God leads him in the years to come. Happy birthday, monkey! We love you! ❤️."
