The drama, which is based on the life of Walter O'Brien, will be penned by Nick Santora and Nicholas Wootton. Justin Lin directs.
"Scorpion," according to the Hollywood Reporter, "revolves around Walter [Elyes Gabel], an eccentric genius, and his international network of super-geniuses who form the last line of defense against the complex threats of the modern age."
McPhee has been cast in the role of Paige, who is described as "a working-class hero and diner waitress who understands geniuses who becomes a nanny of sorts and a translator for Walter's super-team of socially misunderstood masterminds."
The cast will also feature Robert Patrick and Eddie Kaye Thomas.
McPhee rose to fame on Fox-TV's singing competition "American Idol."