Along with his siblings, Nathan was homeschooled growing up. He and his siblings were raised as active participants of Bill Gothard's Institute in Basic Life Principles, and regularly attended the yearly Advanced Training Institute conferences in Big Sandy, Texas.
His parents were strict growing up, and he and his siblings had weekly scheduled fifteen minute meetings of one-on-one time with their parents.
In 1996, his father made the decision to quit his job and begin working in full-time ministry at a local juvenile detention center. Nathan often accompanied his father on these trips and led Bible studies for incarcerated young women.
On July 1, 2019, Nurie Rodrigues announced via a Facebook Live video on her parents' Facebook page that she was courting Nathan Keller. This courtship was teased on her family's Facebook page on June 11, 2019 and her mother's blog on June 26, 2019. Later that day, her mother posted on her Instagram account that the two had been getting to know each other over the years when their families visited and that both she and Nathan were seeking their parents' guidance in the relationship.
In a later Instagram post, it was revealed that the courtship began "about 3 weeks" prior to the public announcement. They officially began courting in early June 2019. Nathan sent Nurie flowers with a note that read: "Dear Nurie, thank you for your friendship for entering this next stage of courtship with me looking forward to what God will do in our future. Love Nathan." Shortly after, Nurie traveled to Georgia with her family to be a bridesmaid in a friend's wedding, which took place on June 29, 2019. Nathan came to Georgia to visit and presented her with a necklace that "made it even more official".
On April 23, 2020, Nathan's 24th birthday, Nurie revealed on her family's Instagram account that they began their relationship on April 23, 2019, Nathan's 23rd birthday.
On November 9, 2019, Nathan proposed to Nurie Rodrigues on a bridge outside of the Stonewall Jackson Resort in Roanoke, West Virginia.
On July 25, 2020, Nathan married Nurie Katelin Rodrigues at Joy Baptist Church in Orrville, Ohio. The couple shared their first kiss at the altar. Nathan's best man was his brother David. His groomsmen were his brother Daniel, his brother-in-law David, and Nurie's brothers Timothy, Phillip, Samuel, and Gabriel. The ring bearer was Nurie's cousin Garrett Foster. Nurie's matron of honor was her mother Jill. Her bridesmaids were her sisters Kaylee and Renee, Nathan's sister Priscilla, and her friends Hosanna Noble and Jasmine Cady. Her junior bridesmaids were her sisters Tessie and Hannah. The flower girls were Nurie's sisters Olivia, Sadie, Sofia, and Janessa.
For their honeymoon, Nathan and Nurie went to a resort in Ohio, Lancaster, Pennsylvania, and Dollywood in Pigeon Forge, Tennessee.
On February 22, 2021, Nathan and Nurie announced that they were expecting their first child, due October 12, 2021. On June 17, 2021, Nathan and Nurie revealed that they were expecting a boy. Nehemiah David Keller was born at 9:44 a.m. on October 11, 2021, at Loving Arms Birth & Wellness Center in Ocala, Florida. He weighed 8 pounds and 2 ounces, and was 21 inches long.
On April 5, 2022, Nurie's mother Jill Rodrigues announced that Nathan and Nurie are expecting their second child, due November 2022. On June 10, 2022, Nurie revealed that she and Nathan are expecting a boy.
Nathan earned his Bachelor of Theology degree at International Baptist Bible College.
Nathan and his brother David currently own and operate Keller Brothers Lawn Care in Palatka, Florida.
In January 2022, Nathan became a Pastor at Anchor Baptist Church in Seville, Florida.
On February 9, 2022, Nathan was charged with not having his son Nehemiah properly restrained in his car seat.