The actress, who also starred on NBC's "Smash," will join a cast that includes Greta Gerwig and Drew Tarver.
"How I Met Your Dad," penned by Emily Spivey and "How I Met Your Mother" creators Carter Bays and Craig Thomas, will tell the story from a female point of view, Sally (Gerwig), and revolves around a new group of friends in New York.
Rodriguez, whose Broadway credits also include Good Vibrations, A Chorus Line, Spring Awakening, In the Heights and The Addams Family, will play Sally's best friend, Juliet, who runs the most successful fashion blog in the country.
The pilot, from 20th TV, will be directed by Pam Fryman.
