McCarney's hiring comes six weeks after former standout high school Todd Dodge was fired following a failed 3 1/2-season experiment.
McCarney has been in college coaching for 34 years, the last three as a defensive coach at Florida. He was also head coach at Iowa State for 12 seasons.
North Texas athletic director Rick Villarreal says it's time for the Mean Green football program to act like a "big-time program." Dodge was 6-37 at North Texas, which has had six consecutive losing seasons in the Sun Belt Conference.