Best known for: Grey's Anatomy, Scandal

Hit-maker Shonda Rhimes belongs to that exclusive club of showrunners who never served on writing staffs prior to creating a show. Rhimes created Grey's Anatomy when she had only a handful of feature writing credits to her name, including The Princess Diaries 2: Royal Engagement, Crossroads, and Introducing Dorothy Dandridge. Rhimes's success was by no means overnight: Years of working in film development preceded the launch of her writing career.