Prior to his relationship with Clarkson, Blackstock was married to Melissa Ashworth from 1999 to 2012. The former couple shared daughter Savannah Blackstock, 23, and son Seth Blackstock, 18. Blackstock became a grandfather in January 2022 when Savannah Blackstock welcomed the first of her two children, with a third currently on the way.

Kelly Clarkson canceled her appearance at the Band Together Texas Benefit following the death of her ex-husband Brandon Blackstock. She and the late music manager share daughter River and son Remington.