His first three films were for the Leucadia Film Corporation: Just like Dad (1995) and Wish Upon a Star (1996), which both received a Crystal Heart Award at the Heartland Film Festival, and The Paper Brigade (1996).
Treu then moved to Southern California and began to work as a director for several episodes of the various Power Rangers series including Power Rangers Turbo (1997), Power Rangers In Space (1998) and Power Rangers Lost Galaxy (1999). He also directed for the TV series Chicken Soup for the Soul. While in Southern California, Treu went to work for the Walt Disney Company. He directed two Disney Channel Movies in the year 2000: Phantom of the Megaplex and The Brainiacs.com.
His third Crystal Heart Award was received for his work on Little Secrets in 2001. In 2007, he directed the TV Movie The Last Day of Summer. In 2009, his series, Real Families, Real Answers, received a Rocky Mountain Regional Emmy nomination. He teamed up with BYU professor Stephan F. Duncan as well as KBYU-TV and BYU Television to create the series.
Treu was the writer, director and producer for the LDS Church's 2014 full length feature film Meet the Mormons.
In 2014, he gave a presentation to over fifty media arts students and faculty at BYU. Blair talked about his experiences getting started as a director in Los Angeles in the early 1980’s. The following year, he was one of the alumni highlighted by the College of Fine Arts and Communications for the celebration of the 50th Anniversary of the Harris Fine Arts Center.