The Kellers raised their children with strict rules, and had weekly 15-minute meetings scheduled for each individual child to talk with his or her parents. When she was ten years old, she felt convicted of her sin and prayed with her dad for salvation. In 1996, her father made the decision to quit his job and begin working in full-time ministry at a local juvenile detention center. Priscilla often accompanied her father on these trips and lead Bible studies for incarcerated young women. Along with her siblings, Priscilla was home-schooled, and completed high school at the age of sixteen.
In September of 2007, Priscilla attended Journey to the Heart with her sister Anna, and felt inspired to work for Journey to the Heart after that. She spent the next three years leading Journeys, as well as ministering in Romania, Mexico, Singapore, Malaysia, and Peru. She also began working for the Institute in Basic Life Principles at their headquarters in Chicago, which is where she met her future husband David Waller.
On September 12, 2011, Priscilla discussed her desire to enter a courtship with David Waller with her father, who had recently received a phone call where David had asked his permission to court Priscilla. On September 20, 2011, David officially asked Priscilla to enter a courtship with her. The two courted for two months.
On November 16, 2011, the couple went out with some of Priscilla's family members to Ravine Gardens and had pancakes. David read Priscilla a letter he had written to her before proposing, which she accepted.
Priscilla married David Waller on February 4, 2012 at Buford Grove Baptist Church in Hilliard, Florida. Their wedding is featured on the 19 Kids and Counting episode "Duggars Down the Aisle". The two went to the Philippines for their honeymoon. They have also visited Romania and Australia. The couple currently lives in Texas where David works at the headquarters for the Institute of Basic Life Principles.
On September 6, 2012, David and Priscilla announced that they were expecting their first child. On October 18, 2012, they announced that their first child would be a son, and that he was due March 9.
Their first child, son Paul William, was born on March 16, 2013, at 3:42 a.m., weighing 9 pounds and 11 ounces and measuring 22 inches long.
On April 9, 2014, David and Priscilla announced that they were expecting their second child in November. They had a gender reveal party in August where they learned that their second child would be a girl. This party was featured on 19 Kids and Counting.
Their second child, daughter Davia Lynn, was born on November 12, 2014, at 10:30 a.m., weighing 8 pounds and 10 ounces and measuring 21 inches long.
On February 21, 2016, David and Priscilla announced that they were expecting their third child in October. On June 12, 2016, they announced that they would be waiting to find out the gender of this child until birth.
Their third child, son Phillip Andrew, was born on October 19, 2016, at 7:29 p.m., weighing 9 pounds and 7 ounces and measuring 22 inches long.
On April 12, 2018, David and Priscilla announced that they were expecting their fourth child in September. They had a gender reveal April 20, 2018 hosted by Priscilla's sister Anna at her and David's home in Texas. The child was revealed to be a girl.
Their fourth child, daughter Destiny Faith was born on October 2, 2018, at 10:53 a.m., weighing 8 pounds and 5 ounces and measuring 22¼ inches long.
On December 3, 2019, David and Priscilla announced that they were expecting their fifth child in May 2020. On Christmas Day of 2019, they revealed that the child will be a boy. Their son, Peter David, was born on May 6, 2020.