John Piper is one of the most influential theologians in America. His son Abraham calls evangelicalism “a destructive, narrow-minded worldview.”

Abraham Piper became a sensation on TikTok nearly overnight. He posted his first video in November, and he now has more than 900,000 followers, many of them young people who thank him for capturing their experiences so precisely. His unlikely path to online stardom: irreverent critiques of evangelical Christianity aimed at others who have left the faith.

“If you just want to roll your eyes at how weird it all was, that’s what I’m here for,” Mr. Piper said, using a vulgarity, in a clip that has been viewed more than 800,000 times since he posted it to the video-sharing site in February.

Mr. Piper is certainly not the only one to use social media to talk about religion. But for millions of current and former evangelicals, there is an extra layer of meaning in his recent emergence as a critic: The household he grew up in was headed by one of the most prominent figures in American evangelicalism. Abraham’s father, John Piper, is a best-selling author and theologian who regularly appears on lists of the most influential pastors in America; he retired as pastor of Bethlehem Baptist Church in Minneapolis in 2013 after 33 years.