At 21, Miller left his home in Pearland, Texas, and went to Portland, Oregon, where he owned a small Portland-based textbook publishing company called Coffee House Books.
In 2004, Miller released Searching For God Knows What, which discusses how the traditional understanding of the gospel of Jesus aligns with a theory of personality.
In 2005, he released Through Painted Deserts, a republished version of his first book, Prayer and the Art of Volkswagen Maintenance, originally published in 2000.
In 2015, he published a book called Scary Close, discussing his views and personal history of self-discovery and intimacy in relationships.
In 2015 Miller helped The Federation for Children create the Failing Our Kids campaign that lobbied state governments for school voucher programs.